linux系统调优
kernel.sched_child_runs_first = 0 kernel.sched_min_granularity_ns = 3000000 kernel.sched_latency_ns = 15000000 kernel.sched_wakeup_granularity_ns = 3000000 kernel.sched_tunable_scaling = 1 kernel.sched_features = 3183 kernel.sched_migration_cost = 500000 kernel.sched_nr_migrate = 32 kernel.sched_time_avg = 1000 kernel.sched_shares_window = 10000000 kernel.timer_migration = 1 kernel.sched_rt_period_us = 1000000 kernel.sched_rt_runtime_us = 950000 kernel.sched_compat_yield = 0 kernel.sched_rr_timeslice_ms = 100 kernel.sched_autogroup_enabled = 0 kernel.sched_cfs_bandwidth_slice_us = 5000 kernel.panic = 0 kernel.exec-shield = 1 kernel.core_uses_pid = 1 kernel.core_pattern = core kernel.core_pipe_limit = 0 kernel.tainted = 0 kernel.real-root-dev = 0 kernel.print-fatal-signals = 0 kernel.ctrl-alt-del = 0 kernel.ftrace_enabled = 1 kernel.stack_tracer_enabled = 0 kernel.ftrace_dump_on_oops = 0 kernel.modprobe = /sbin/modprobe kernel.modules_disabled = 0 kernel.kexec_load_disabled = 0 kernel.hotplug = kernel.acct = 4 2 30 kernel.sysrq = 0 kernel.cad_pid = 1 kernel.threads-max = 62803 kernel.random.poolsize = 4096 kernel.random.entropy_avail = 168 kernel.random.read_wakeup_threshold = 64 kernel.random.write_wakeup_threshold = 128 kernel.random.boot_id = 3b7f0235-9995-4885-91ce-ea8f614896ac kernel.random.uuid = 349859da-0492-4b69-aaba-eef98ad0a663 kernel.usermodehelper.bset = 4294967295 4294967295 kernel.usermodehelper.inheritable = 4294967295 4294967295 kernel.overflowuid = 65534 kernel.overflowgid = 65534 kernel.pid_max = 32768 kernel.panic_on_oops = 1 kernel.printk = 4 4 1 7 kernel.printk_ratelimit = 5 kernel.printk_ratelimit_burst = 10 kernel.printk_delay = 0 kernel.dmesg_restrict = 0 kernel.kptr_restrict = 1 kernel.ngroups_max = 65536 kernel.cap_last_cap = 33 kernel.watchdog = 1 kernel.watchdog_thresh = 60 kernel.softlockup_panic = 0 kernel.softlockup_all_cpu_backtrace = 0 kernel.nmi_watchdog = 1 kernel.unknown_nmi_panic = 0 kernel.panic_on_unrecovered_nmi = 0 kernel.panic_on_io_nmi = 0 kernel.bootloader_type = 113 kernel.bootloader_version = 1 kernel.kstack_depth_to_print = 12 kernel.io_delay_type = 0 kernel.randomize_va_space = 2 kernel.acpi_video_flags = 0 kernel.hung_task_panic = 0 kernel.hung_task_check_count = 4194304 kernel.hung_task_timeout_secs = 120 kernel.hung_task_warnings = 10 kernel.compat-log = 1 kernel.max_lock_depth = 1024 kernel.poweroff_cmd = /sbin/poweroff kernel.keys.maxkeys = 200 kernel.keys.maxbytes = 20000 kernel.keys.root_maxkeys = 1000000 kernel.keys.root_maxbytes = 25000000 kernel.keys.gc_delay = 300 kernel.slow-work.min-threads = 2 kernel.slow-work.max-threads = 4 kernel.slow-work.vslow-percentage = 50 kernel.perf_event_paranoid = 1 kernel.perf_event_mlock_kb = 516 kernel.perf_event_max_sample_rate = 100000 kernel.blk_iopoll = 1 kernel.panic_on_warn = 0 kernel.sched_domain.cpu0.domain0.min_interval = 1 kernel.sched_domain.cpu0.domain0.max_interval = 4 kernel.sched_domain.cpu0.domain0.busy_idx = 2 kernel.sched_domain.cpu0.domain0.idle_idx = 0 kernel.sched_domain.cpu0.domain0.newidle_idx = 0 kernel.sched_domain.cpu0.domain0.wake_idx = 0 kernel.sched_domain.cpu0.domain0.forkexec_idx = 0 kernel.sched_domain.cpu0.domain0.busy_factor = 64 kernel.sched_domain.cpu0.domain0.imbalance_pct = 125 kernel.sched_domain.cpu0.domain0.cache_nice_tries = 1 kernel.sched_domain.cpu0.domain0.flags = 4655 kernel.sched_domain.cpu0.domain0.name = MC kernel.sched_domain.cpu1.domain0.min_interval = 1 kernel.sched_domain.cpu1.domain0.max_interval = 4 kernel.sched_domain.cpu1.domain0.busy_idx = 2 kernel.sched_domain.cpu1.domain0.idle_idx = 0 kernel.sched_domain.cpu1.domain0.newidle_idx = 0 kernel.sched_domain.cpu1.domain0.wake_idx = 0 kernel.sched_domain.cpu1.domain0.forkexec_idx = 0 kernel.sched_domain.cpu1.domain0.busy_factor = 64 kernel.sched_domain.cpu1.domain0.imbalance_pct = 125 kernel.sched_domain.cpu1.domain0.cache_nice_tries = 1 kernel.sched_domain.cpu1.domain0.flags = 4655 kernel.sched_domain.cpu1.domain0.name = MC kernel.sched_domain.cpu2.domain0.min_interval = 1 kernel.sched_domain.cpu2.domain0.max_interval = 4 kernel.sched_domain.cpu2.domain0.busy_idx = 2 kernel.sched_domain.cpu2.domain0.idle_idx = 0 kernel.sched_domain.cpu2.domain0.newidle_idx = 0 kernel.sched_domain.cpu2.domain0.wake_idx = 0 kernel.sched_domain.cpu2.domain0.forkexec_idx = 0 kernel.sched_domain.cpu2.domain0.busy_factor = 64 kernel.sched_domain.cpu2.domain0.imbalance_pct = 125 kernel.sched_domain.cpu2.domain0.cache_nice_tries = 1 kernel.sched_domain.cpu2.domain0.flags = 4655 kernel.sched_domain.cpu2.domain0.name = MC kernel.sched_domain.cpu3.domain0.min_interval = 1 kernel.sched_domain.cpu3.domain0.max_interval = 4 kernel.sched_domain.cpu3.domain0.busy_idx = 2 kernel.sched_domain.cpu3.domain0.idle_idx = 0 kernel.sched_domain.cpu3.domain0.newidle_idx = 0 kernel.sched_domain.cpu3.domain0.wake_idx = 0 kernel.sched_domain.cpu3.domain0.forkexec_idx = 0 kernel.sched_domain.cpu3.domain0.busy_factor = 64 kernel.sched_domain.cpu3.domain0.imbalance_pct = 125 kernel.sched_domain.cpu3.domain0.cache_nice_tries = 1 kernel.sched_domain.cpu3.domain0.flags = 4655 kernel.sched_domain.cpu3.domain0.name = MC kernel.vsyscall64 = 1 kernel.ostype = Linux kernel.osrelease = 2.6.32-573.22.1.el6.x86_64 kernel.version = #1 SMP Wed Mar 23 03:35:39 UTC 2016 kernel.hostname = ap-uce-uop-mq kernel.domainname = (none) kernel.pty.max = 4096 kernel.pty.nr = 1 kernel.shmmax = 68719476736 kernel.shmall = 4294967296 kernel.shmmni = 4096 kernel.shm_rmid_forced = 0 kernel.msgmax = 65536 kernel.msgmni = 15737 kernel.msgmnb = 65536 kernel.sem = 250 32000 32 128 kernel.auto_msgmni = 1 vm.overcommit_memory = 0 vm.panic_on_oom = 0 vm.oom_kill_allocating_task = 0 vm.extfrag_threshold = 500 vm.oom_dump_tasks = 1 vm.would_have_oomkilled = 0 vm.overcommit_ratio = 50 vm.overcommit_kbytes = 0 vm.page-cluster = 3 vm.dirty_background_ratio = 10 vm.dirty_background_bytes = 0 vm.dirty_ratio = 20 vm.dirty_bytes = 0 vm.dirty_writeback_centisecs = 500 vm.dirty_expire_centisecs = 3000 vm.nr_pdflush_threads = 0 vm.swappiness = 0 vm.nr_hugepages = 0 vm.nr_hugepages_mempolicy = 0 vm.hugetlb_shm_group = 0 vm.hugepages_treat_as_movable = 0 vm.nr_overcommit_hugepages = 0 vm.lowmem_reserve_ratio = 256 256 32 vm.drop_caches = 0 vm.min_free_kbytes = 67584 vm.extra_free_kbytes = 0 vm.unmap_area_factor = 0 vm.meminfo_legacy_layout = 1 vm.percpu_pagelist_fraction = 0 vm.max_map_count = 65530 vm.laptop_mode = 0 vm.block_dump = 0 vm.vfs_cache_pressure = 100 vm.legacy_va_layout = 0 vm.zone_reclaim_mode = 0 vm.min_unmapped_ratio = 1 vm.min_slab_ratio = 5 vm.stat_interval = 1 vm.mmap_min_addr = 4096 vm.numa_zonelist_order = default vm.scan_unevictable_pages = 0 vm.memory_failure_early_kill = 0 vm.memory_failure_recovery = 1 vm.admin_reserve_kbytes = 8192 fs.inode-nr = 43147 2072 fs.inode-state = 43147 2072 0 0 0 0 0 fs.file-nr = 736 0 798336 fs.file-max = 798336 fs.nr_open = 1048576 fs.dentry-state = 43591 37426 45 0 0 0 fs.overflowuid = 65534 fs.overflowgid = 65534 fs.leases-enable = 1 fs.dir-notify-enable = 1 fs.lease-break-time = 45 fs.aio-nr = 0 fs.aio-max-nr = 65536 fs.inotify.max_user_instances = 128 fs.inotify.max_user_watches = 8192 fs.inotify.max_queued_events = 16384 fs.epoll.max_user_watches = 1646346 fs.suid_dumpable = 0 fs.binfmt_misc.status = enabled fs.quota.lookups = 0 fs.quota.drops = 0 fs.quota.reads = 0 fs.quota.writes = 0 fs.quota.cache_hits = 0 fs.quota.allocated_dquots = 0 fs.quota.free_dquots = 0 fs.quota.syncs = 2 fs.quota.warnings = 1 fs.mqueue.queues_max = 256 fs.mqueue.msg_max = 10 fs.mqueue.msgsize_max = 8192 fs.mqueue.msg_default = 10 fs.mqueue.msgsize_default = 8192 fs.nfs.nlm_grace_period = 0 fs.nfs.nlm_timeout = 10 fs.nfs.nlm_udpport = 0 fs.nfs.nlm_tcpport = 0 fs.nfs.nsm_use_hostnames = 0 fs.nfs.nsm_local_state = 0 fs.nfs.nfs_callback_tcpport = 0 fs.nfs.idmap_cache_timeout = 600 fs.nfs.nfs_mountpoint_timeout = 500 fs.nfs.nfs_congestion_kb = 90816 debug.exception-trace = 1 debug.kprobes-optimization = 1 dev.scsi.logging_level = 0 dev.raid.speed_limit_min = 1000 dev.raid.speed_limit_max = 200000 dev.hpet.max-user-freq = 64 dev.mac_hid.mouse_button_emulation = 0 dev.mac_hid.mouse_button2_keycode = 97 dev.mac_hid.mouse_button3_keycode = 100 dev.cdrom.info = CD-ROM information, Id: cdrom.c 3.20 2003/12/17 dev.cdrom.info = dev.cdrom.info = drive name: sr0 dev.cdrom.info = drive speed: 4 dev.cdrom.info = drive # of slots: 1 dev.cdrom.info = Can close tray: 1 dev.cdrom.info = Can open tray: 1 dev.cdrom.info = Can lock tray: 1 dev.cdrom.info = Can change speed: 1 dev.cdrom.info = Can select disk: 0 dev.cdrom.info = Can read multisession: 1 dev.cdrom.info = Can read MCN: 1 dev.cdrom.info = Reports media changed: 1 dev.cdrom.info = Can play audio: 1 dev.cdrom.info = Can write CD-R: 0 dev.cdrom.info = Can write CD-RW: 0 dev.cdrom.info = Can read DVD: 1 dev.cdrom.info = Can write DVD-R: 0 dev.cdrom.info = Can write DVD-RAM: 0 dev.cdrom.info = Can read MRW: 1 dev.cdrom.info = Can write MRW: 1 dev.cdrom.info = Can write RAM: 1 dev.cdrom.info = dev.cdrom.info = dev.cdrom.autoclose = 1 dev.cdrom.autoeject = 0 dev.cdrom.debug = 0 dev.cdrom.lock = 1 dev.cdrom.check_media = 0 net.netfilter.nf_log.0 = NONE net.netfilter.nf_log.1 = NONE net.netfilter.nf_log.2 = NONE net.netfilter.nf_log.3 = NONE net.netfilter.nf_log.4 = NONE net.netfilter.nf_log.5 = NONE net.netfilter.nf_log.6 = NONE net.netfilter.nf_log.7 = NONE net.netfilter.nf_log.8 = NONE net.netfilter.nf_log.9 = NONE net.netfilter.nf_log.10 = NONE net.netfilter.nf_log.11 = NONE net.netfilter.nf_log.12 = NONE net.core.somaxconn = 128 net.core.xfrm_aevent_etime = 10 net.core.xfrm_aevent_rseqth = 2 net.core.xfrm_larval_drop = 1 net.core.xfrm_acq_expires = 30 net.core.wmem_max = 124928 net.core.rmem_max = 124928 net.core.wmem_default = 124928 net.core.rmem_default = 124928 net.core.dev_weight = 64 net.core.netdev_max_backlog = 1000 net.core.netdev_rss_key = 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 net.core.message_cost = 5 net.core.message_burst = 10 net.core.optmem_max = 20480 net.core.rps_sock_flow_entries = 0 net.core.busy_poll = 0 net.core.busy_read = 0 net.core.netdev_budget = 300 net.core.warnings = 1 net.ipv4.route.gc_thresh = 262144 net.ipv4.route.max_size = 4194304 net.ipv4.route.gc_min_interval = 0 net.ipv4.route.gc_min_interval_ms = 500 net.ipv4.route.gc_timeout = 300 net.ipv4.route.gc_interval = 60 net.ipv4.route.redirect_load = 20 net.ipv4.route.redirect_number = 9 net.ipv4.route.redirect_silence = 20480 net.ipv4.route.error_cost = 1000 net.ipv4.route.error_burst = 5000 net.ipv4.route.gc_elasticity = 8 net.ipv4.route.mtu_expires = 600 net.ipv4.route.min_pmtu = 552 net.ipv4.route.min_adv_mss = 256 net.ipv4.route.secret_interval = 600 net.ipv4.neigh.default.mcast_solicit = 3 net.ipv4.neigh.default.ucast_solicit = 3 net.ipv4.neigh.default.app_solicit = 0 net.ipv4.neigh.default.retrans_time = 99 net.ipv4.neigh.default.base_reachable_time = 30 net.ipv4.neigh.default.delay_first_probe_time = 5 net.ipv4.neigh.default.gc_stale_time = 120 net.ipv4.neigh.default.unres_qlen = 3 net.ipv4.neigh.default.proxy_qlen = 64 net.ipv4.neigh.default.anycast_delay = 99 net.ipv4.neigh.default.proxy_delay = 79 net.ipv4.neigh.default.locktime = 99 net.ipv4.neigh.default.retrans_time_ms = 1000 net.ipv4.neigh.default.base_reachable_time_ms = 30000 net.ipv4.neigh.default.gc_interval = 30 net.ipv4.neigh.default.gc_thresh1 = 128 net.ipv4.neigh.default.gc_thresh2 = 512 net.ipv4.neigh.default.gc_thresh3 = 1024 net.ipv4.neigh.lo.mcast_solicit = 3 net.ipv4.neigh.lo.ucast_solicit = 3 net.ipv4.neigh.lo.app_solicit = 0 net.ipv4.neigh.lo.retrans_time = 99 net.ipv4.neigh.lo.base_reachable_time = 30 net.ipv4.neigh.lo.delay_first_probe_time = 5 net.ipv4.neigh.lo.gc_stale_time = 60 net.ipv4.neigh.lo.unres_qlen = 3 net.ipv4.neigh.lo.proxy_qlen = 64 net.ipv4.neigh.lo.anycast_delay = 99 net.ipv4.neigh.lo.proxy_delay = 79 net.ipv4.neigh.lo.locktime = 99 net.ipv4.neigh.lo.retrans_time_ms = 1000 net.ipv4.neigh.lo.base_reachable_time_ms = 30000 net.ipv4.neigh.eth0.mcast_solicit = 3 net.ipv4.neigh.eth0.ucast_solicit = 3 net.ipv4.neigh.eth0.app_solicit = 0 net.ipv4.neigh.eth0.retrans_time = 99 net.ipv4.neigh.eth0.base_reachable_time = 30 net.ipv4.neigh.eth0.delay_first_probe_time = 5 net.ipv4.neigh.eth0.gc_stale_time = 120 net.ipv4.neigh.eth0.unres_qlen = 3 net.ipv4.neigh.eth0.proxy_qlen = 64 net.ipv4.neigh.eth0.anycast_delay = 99 net.ipv4.neigh.eth0.proxy_delay = 79 net.ipv4.neigh.eth0.locktime = 99 net.ipv4.neigh.eth0.retrans_time_ms = 1000 net.ipv4.neigh.eth0.base_reachable_time_ms = 30000 net.ipv4.tcp_timestamps = 1 net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_sack = 1 net.ipv4.tcp_retrans_collapse = 1 net.ipv4.ip_default_ttl = 64 net.ipv4.ip_nonlocal_bind = 0 net.ipv4.tcp_syn_retries = 5 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_max_orphans = 262144 net.ipv4.tcp_max_tw_buckets = 5000 net.ipv4.ip_dynaddr = 0 net.ipv4.tcp_keepalive_time = 7200 net.ipv4.tcp_keepalive_probes = 9 net.ipv4.tcp_keepalive_intvl = 75 net.ipv4.tcp_retries1 = 3 net.ipv4.tcp_retries2 = 15 net.ipv4.tcp_fin_timeout = 60 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_tw_recycle = 0 net.ipv4.tcp_abort_on_overflow = 0 net.ipv4.tcp_stdurg = 0 net.ipv4.tcp_rfc1337 = 0 net.ipv4.tcp_max_syn_backlog = 1024 net.ipv4.ip_local_port_range = 32768 61000 net.ipv4.ip_local_reserved_ports = net.ipv4.igmp_max_memberships = 20 net.ipv4.igmp_max_msf = 10 net.ipv4.inet_peer_threshold = 65664 net.ipv4.inet_peer_minttl = 120 net.ipv4.inet_peer_maxttl = 600 net.ipv4.inet_peer_gc_mintime = 10 net.ipv4.inet_peer_gc_maxtime = 120 net.ipv4.tcp_orphan_retries = 0 net.ipv4.tcp_fack = 1 net.ipv4.tcp_reordering = 3 net.ipv4.tcp_ecn = 2 net.ipv4.tcp_dsack = 1 net.ipv4.tcp_mem = 753600 1004800 1507200 net.ipv4.tcp_wmem = 4096 16384 4194304 net.ipv4.tcp_rmem = 4096 87380 4194304 net.ipv4.tcp_app_win = 31 net.ipv4.tcp_adv_win_scale = 2 net.ipv4.tcp_tw_reuse = 0 net.ipv4.tcp_frto = 2 net.ipv4.tcp_frto_response = 0 net.ipv4.tcp_low_latency = 0 net.ipv4.tcp_no_metrics_save = 0 net.ipv4.tcp_moderate_rcvbuf = 1 net.ipv4.tcp_tso_win_divisor = 3 net.ipv4.tcp_congestion_control = cubic net.ipv4.tcp_abc = 0 net.ipv4.tcp_mtu_probing = 0 net.ipv4.tcp_base_mss = 512 net.ipv4.tcp_workaround_signed_windows = 0 net.ipv4.tcp_challenge_ack_limit = 100 net.ipv4.tcp_limit_output_bytes = 262144 net.ipv4.tcp_dma_copybreak = 4096 net.ipv4.tcp_slow_start_after_idle = 1 net.ipv4.cipso_cache_enable = 1 net.ipv4.cipso_cache_bucket_size = 10 net.ipv4.cipso_rbm_optfmt = 0 net.ipv4.cipso_rbm_strictvalid = 1 net.ipv4.tcp_available_congestion_control = cubic reno net.ipv4.tcp_allowed_congestion_control = cubic reno net.ipv4.tcp_max_ssthresh = 0 net.ipv4.tcp_thin_linear_timeouts = 0 net.ipv4.tcp_thin_dupack = 0 net.ipv4.tcp_min_tso_segs = 2 net.ipv4.udp_mem = 753600 1004800 1507200 net.ipv4.udp_rmem_min = 4096 net.ipv4.udp_wmem_min = 4096 net.ipv4.conf.all.forwarding = 0 net.ipv4.conf.all.mc_forwarding = 0 net.ipv4.conf.all.accept_redirects = 1 net.ipv4.conf.all.secure_redirects = 1 net.ipv4.conf.all.shared_media = 1 net.ipv4.conf.all.rp_filter = 0 net.ipv4.conf.all.send_redirects = 1 net.ipv4.conf.all.accept_source_route = 0 net.ipv4.conf.all.src_valid_mark = 0 net.ipv4.conf.all.proxy_arp = 0 net.ipv4.conf.all.medium_id = 0 net.ipv4.conf.all.bootp_relay = 0 net.ipv4.conf.all.log_martians = 0 net.ipv4.conf.all.tag = 0 net.ipv4.conf.all.arp_filter = 0 net.ipv4.conf.all.arp_announce = 2 net.ipv4.conf.all.arp_ignore = 0 net.ipv4.conf.all.arp_accept = 0 net.ipv4.conf.all.arp_notify = 0 net.ipv4.conf.all.proxy_arp_pvlan = 0 net.ipv4.conf.all.disable_xfrm = 0 net.ipv4.conf.all.disable_policy = 0 net.ipv4.conf.all.force_igmp_version = 0 net.ipv4.conf.all.promote_secondaries = 0 net.ipv4.conf.all.accept_local = 0 net.ipv4.conf.all.route_localnet = 0 net.ipv4.conf.default.forwarding = 0 net.ipv4.conf.default.mc_forwarding = 0 net.ipv4.conf.default.accept_redirects = 1 net.ipv4.conf.default.secure_redirects = 1 net.ipv4.conf.default.shared_media = 1 net.ipv4.conf.default.rp_filter = 0 net.ipv4.conf.default.send_redirects = 1 net.ipv4.conf.default.accept_source_route = 0 net.ipv4.conf.default.src_valid_mark = 0 net.ipv4.conf.default.proxy_arp = 0 net.ipv4.conf.default.medium_id = 0 net.ipv4.conf.default.bootp_relay = 0 net.ipv4.conf.default.log_martians = 0 net.ipv4.conf.default.tag = 0 net.ipv4.conf.default.arp_filter = 0 net.ipv4.conf.default.arp_announce = 2 net.ipv4.conf.default.arp_ignore = 0 net.ipv4.conf.default.arp_accept = 0 net.ipv4.conf.default.arp_notify = 0 net.ipv4.conf.default.proxy_arp_pvlan = 0 net.ipv4.conf.default.disable_xfrm = 0 net.ipv4.conf.default.disable_policy = 0 net.ipv4.conf.default.force_igmp_version = 0 net.ipv4.conf.default.promote_secondaries = 0 net.ipv4.conf.default.accept_local = 0 net.ipv4.conf.default.route_localnet = 0 net.ipv4.conf.lo.forwarding = 0 net.ipv4.conf.lo.mc_forwarding = 0 net.ipv4.conf.lo.accept_redirects = 1 net.ipv4.conf.lo.secure_redirects = 1 net.ipv4.conf.lo.shared_media = 1 net.ipv4.conf.lo.rp_filter = 0 net.ipv4.conf.lo.send_redirects = 1 net.ipv4.conf.lo.accept_source_route = 1 net.ipv4.conf.lo.src_valid_mark = 0 net.ipv4.conf.lo.proxy_arp = 0 net.ipv4.conf.lo.medium_id = 0 net.ipv4.conf.lo.bootp_relay = 0 net.ipv4.conf.lo.log_martians = 0 net.ipv4.conf.lo.tag = 0 net.ipv4.conf.lo.arp_filter = 0 net.ipv4.conf.lo.arp_announce = 2 net.ipv4.conf.lo.arp_ignore = 0 net.ipv4.conf.lo.arp_accept = 0 net.ipv4.conf.lo.arp_notify = 0 net.ipv4.conf.lo.proxy_arp_pvlan = 0 net.ipv4.conf.lo.disable_xfrm = 1 net.ipv4.conf.lo.disable_policy = 1 net.ipv4.conf.lo.force_igmp_version = 0 net.ipv4.conf.lo.promote_secondaries = 0 net.ipv4.conf.lo.accept_local = 0 net.ipv4.conf.lo.route_localnet = 0 net.ipv4.conf.eth0.forwarding = 0 net.ipv4.conf.eth0.mc_forwarding = 0 net.ipv4.conf.eth0.accept_redirects = 1 net.ipv4.conf.eth0.secure_redirects = 1 net.ipv4.conf.eth0.shared_media = 1 net.ipv4.conf.eth0.rp_filter = 0 net.ipv4.conf.eth0.send_redirects = 1 net.ipv4.conf.eth0.accept_source_route = 0 net.ipv4.conf.eth0.src_valid_mark = 0 net.ipv4.conf.eth0.proxy_arp = 0 net.ipv4.conf.eth0.medium_id = 0 net.ipv4.conf.eth0.bootp_relay = 0 net.ipv4.conf.eth0.log_martians = 0 net.ipv4.conf.eth0.tag = 0 net.ipv4.conf.eth0.arp_filter = 0 net.ipv4.conf.eth0.arp_announce = 2 net.ipv4.conf.eth0.arp_ignore = 0 net.ipv4.conf.eth0.arp_accept = 0 net.ipv4.conf.eth0.arp_notify = 0 net.ipv4.conf.eth0.proxy_arp_pvlan = 0 net.ipv4.conf.eth0.disable_xfrm = 0 net.ipv4.conf.eth0.disable_policy = 0 net.ipv4.conf.eth0.force_igmp_version = 0 net.ipv4.conf.eth0.promote_secondaries = 0 net.ipv4.conf.eth0.accept_local = 0 net.ipv4.conf.eth0.route_localnet = 0 net.ipv4.ip_forward = 0 net.ipv4.xfrm4_gc_thresh = 2097152 net.ipv4.ipfrag_high_thresh = 4194304 net.ipv4.ipfrag_low_thresh = 3145728 net.ipv4.ipfrag_time = 30 net.ipv4.icmp_echo_ignore_all = 0 net.ipv4.icmp_echo_ignore_broadcasts = 1 net.ipv4.icmp_ignore_bogus_error_responses = 1 net.ipv4.icmp_errors_use_inbound_ifaddr = 0 net.ipv4.icmp_ratelimit = 1000 net.ipv4.icmp_ratemask = 6168 net.ipv4.rt_cache_rebuild_count = 4 net.ipv4.ping_group_range = 1 0 net.ipv4.ip_no_pmtu_disc = 0 net.ipv4.ip_forward_use_pmtu = 0 net.ipv4.ipfrag_secret_interval = 600 net.ipv4.ipfrag_max_dist = 64 net.unix.max_dgram_qlen = 10 abi.vsyscall32 = 1 crypto.fips_enabled = 0 sunrpc.rpc_debug = 0 sunrpc.nfs_debug = 0 sunrpc.nfsd_debug = 0 sunrpc.nlm_debug = 0 sunrpc.transports = tcp 1048576 sunrpc.transports = udp 32768 sunrpc.transports = tcp-bc 1048576 sunrpc.udp_slot_table_entries = 16 sunrpc.tcp_slot_table_entries = 2 sunrpc.tcp_max_slot_table_entries = 65536 sunrpc.min_resvport = 665 sunrpc.max_resvport = 1023 sunrpc.tcp_fin_timeout = 15
kernel.sched_child_runs_first = 0
sysctl_sched_child_runs_first，该变量表示在创建子进程的时候是否让子进程抢占父进程，即使父进程的vruntime小于子进程，这个会减少公平性，但是可以降低write_on_copy，具体要根据系统的应用情况来考量使用哪种方式（见task_fork_fair过程）
kernel.sched_min_granularity_ns = 3000000
（4000000ns）：sysctl_sched_min_granularity，表示进程最少运行时间，防止频繁的切换，对于交互系统（如桌面），该值可以设置得较小，这样可以保证交互得到更快的响应（见周期调度器的check_preempt_tick过程）
kernel.sched_latency_ns = 15000000
sysctl_sched_latency，表示一个运行队列所有进程运行一次的周期，当前这个与运行队列的进程数有关，如果进程数超过sched_nr_latency（这个变量不能通过/proc设置，它是由(sysctl_sched_latency+ sysctl_sched_min_granularity-1)/sysctl_sched_min_granularity确定的），那么调度周期就是sched_min_granularity_ns*运行队列里的进程数，与sysctl_sched_latency无关；否则队列进程数小于sched_nr_latency，运行周期就是sysctl_sched_latency。显然这个数越小，一个运行队列支持的sched_nr_latency越少，而且当sysctl_sched_min_granularity越小时能支持的sched_nr_latency越多，那么每个进程在这个周期内能执行的时间也就越少，这也与上面sysctl_sched_min_granularity变量的讨论一致。其实sched_nr_latency也可以当做我们cpu load的基准值，如果cpu的load大于这个值，那么说明cpu不够使用了
kernel.sched_wakeup_granularity_ns = 3000000
sysctl_sched_wakeup_granularity，该变量表示进程被唤醒后至少应该运行的时间的基数，它只是用来判断某个进程是否应该抢占当前进程，并不代表它能够执行的最小时间（sysctl_sched_min_granularity），如果这个数值越小，那么发生抢占的概率也就越高（见wakeup_gran、wakeup_preempt_entity函数）
kernel.sched_tunable_scaling = 1
sysctl_sched_tunable_scaling，当内核试图调整sched_min_granularity，sched_latency和sched_wakeup_granularity这三个值的时候所使用的更新方法，0为不调整，1为按照cpu个数以2为底的对数值进行调整，2为按照cpu的个数进行线性比例的调整
kernel.sched_features = 3183
sysctl_sched_features，该变量表示调度器支持的特性，如GENTLE_FAIR_SLEEPERS(平滑的补偿睡眠进程),START_DEBIT(新进程尽量的早调度),WAKEUP_PREEMPT(是否wakeup的进程可以去抢占当前运行的进程)等，所有的features见内核sech_features.h文件的定义
kernel.sched_migration_cost = 500000
sysctl_sched_migration_cost该变量用来判断一个进程是否还是hot，如果进程的运行时间（now - p->se.exec_start）小于它，那么内核认为它的code还在cache里，所以该进程还是hot，那么在迁移的时候就不会考虑它
kernel.sched_nr_migrate = 32
sysctl_sched_nr_migrate，在多CPU情况下进行负载均衡时，一次最多移动多少个进程到另一个CPU上
kernel.sched_time_avg = 1000
kernel.sched_shares_window = 10000000
kernel.timer_migration = 1
kernel.sched_rt_period_us = 1000000
该参数与sched_rt_runtime_us一起决定了实时进程在以sched_rt_period为周期的时间内，实时进程最多能够运行的总的时间不能超过sched_rt_runtime_us
kernel.sched_rt_runtime_us = 950000
该参数与sched_rt_period一起决定了实时进程在以sched_rt_period为周期的时间内，实时进程最多能够运行的总的时间不能超过sched_rt_runtime_us
kernel.sched_compat_yield = 0
kernel.sched_rr_timeslice_ms = 100
用来指示round robin调度进程的间隔，这个间隔默认是100ms
kernel.sched_autogroup_enabled = 0
启用后，内核会创建任务组来优化桌面程序的调度。它将把占用大量资源的应用程序放在它们自己的任务组，这有助于性能提升
0：禁止
1：开启
kernel.sched_cfs_bandwidth_slice_us = 5000
kernel.panic = 0
kernel.exec-shield = 1
kernel.core_uses_pid = 1
kernel.core_pattern = core
kernel.core_pipe_limit = 0
kernel.tainted = 0
kernel.real-root-dev = 0
kernel.print-fatal-signals = 0
kernel.ctrl-alt-del = 0
kernel.ftrace_enabled = 1
kernel.stack_tracer_enabled = 0
kernel.ftrace_dump_on_oops = 0
kernel.modprobe = /sbin/modprobe
kernel.modules_disabled = 0
kernel.kexec_load_disabled = 0
kernel.hotplug =
kernel.acct = 4 2 30
kernel.sysrq = 0
kernel.cad_pid = 1
kernel.threads-max = 62803
kernel.random.poolsize = 4096
kernel.random.entropy_avail = 168
kernel.random.read_wakeup_threshold = 64
kernel.random.write_wakeup_threshold = 128
kernel.random.boot_id = 3b7f0235-9995-4885-91ce-ea8f614896ac
kernel.random.uuid = 349859da-0492-4b69-aaba-eef98ad0a663
kernel.usermodehelper.bset = 4294967295 4294967295
kernel.usermodehelper.inheritable = 4294967295 4294967295
kernel.overflowuid = 65534
kernel.overflowgid = 65534
kernel.pid_max = 32768
kernel.panic_on_oops = 1
kernel.printk = 4 4 1 7
kernel.printk_ratelimit = 5
kernel.printk_ratelimit_burst = 10
kernel.printk_delay = 0
kernel.dmesg_restrict = 0
kernel.kptr_restrict = 1
kernel.ngroups_max = 65536
kernel.cap_last_cap = 33
kernel.watchdog = 1
kernel.watchdog_thresh = 60
kernel.softlockup_panic = 0
设置产生softlockup时是否抛出一个panic。Softlockup用于检测CPU可以响应中断，但是在长时间内不能调度（比如禁止抢占时间太长）的死锁情况。这个机制运行在一个hrtimer的中断上下文，每隔一段时间检测一下是否发生了调度，如果过长时间没发生调度，说明系统被死锁。
0：不产生panic
1：产生panic
kernel.softlockup_all_cpu_backtrace = 0
kernel.nmi_watchdog = 1
使能nmi_watchdog
0：禁止
1：开启
kernel.unknown_nmi_panic = 0
kernel.panic_on_unrecovered_nmi = 0
kernel.panic_on_io_nmi = 0
kernel.bootloader_type = 113
kernel.bootloader_version = 1
kernel.kstack_depth_to_print = 12
kernel.io_delay_type = 0
kernel.randomize_va_space = 2
kernel.acpi_video_flags = 0
kernel.hung_task_panic = 0
kernel.hung_task_check_count = 4194304
kernel.hung_task_timeout_secs = 120
kernel.hung_task_warnings = 10
kernel.compat-log = 1
kernel.max_lock_depth = 1024
kernel.poweroff_cmd = /sbin/poweroff
kernel.keys.maxkeys = 200
kernel.keys.maxbytes = 20000
kernel.keys.root_maxkeys = 1000000
kernel.keys.root_maxbytes = 25000000
kernel.keys.gc_delay = 300
kernel.slow-work.min-threads = 2
kernel.slow-work.max-threads = 4
kernel.slow-work.vslow-percentage = 50
kernel.perf_event_paranoid = 1
kernel.perf_event_mlock_kb = 516
kernel.perf_event_max_sample_rate = 100000
kernel.blk_iopoll = 1
kernel.panic_on_warn = 0
kernel.sched_domain.cpu0.domain0.min_interval = 1
kernel.sched_domain.cpu0.domain0.max_interval = 4
kernel.sched_domain.cpu0.domain0.busy_idx = 2
kernel.sched_domain.cpu0.domain0.idle_idx = 0
kernel.sched_domain.cpu0.domain0.newidle_idx = 0
kernel.sched_domain.cpu0.domain0.wake_idx = 0
kernel.sched_domain.cpu0.domain0.forkexec_idx = 0
kernel.sched_domain.cpu0.domain0.busy_factor = 64
kernel.sched_domain.cpu0.domain0.imbalance_pct = 125
kernel.sched_domain.cpu0.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu0.domain0.flags = 4655
kernel.sched_domain.cpu0.domain0.name = MC
kernel.sched_domain.cpu1.domain0.min_interval = 1
kernel.sched_domain.cpu1.domain0.max_interval = 4
kernel.sched_domain.cpu1.domain0.busy_idx = 2
kernel.sched_domain.cpu1.domain0.idle_idx = 0
kernel.sched_domain.cpu1.domain0.newidle_idx = 0
kernel.sched_domain.cpu1.domain0.wake_idx = 0
kernel.sched_domain.cpu1.domain0.forkexec_idx = 0
kernel.sched_domain.cpu1.domain0.busy_factor = 64
kernel.sched_domain.cpu1.domain0.imbalance_pct = 125
kernel.sched_domain.cpu1.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu1.domain0.flags = 4655
kernel.sched_domain.cpu1.domain0.name = MC
kernel.sched_domain.cpu2.domain0.min_interval = 1
kernel.sched_domain.cpu2.domain0.max_interval = 4
kernel.sched_domain.cpu2.domain0.busy_idx = 2
kernel.sched_domain.cpu2.domain0.idle_idx = 0
kernel.sched_domain.cpu2.domain0.newidle_idx = 0
kernel.sched_domain.cpu2.domain0.wake_idx = 0
kernel.sched_domain.cpu2.domain0.forkexec_idx = 0
kernel.sched_domain.cpu2.domain0.busy_factor = 64
kernel.sched_domain.cpu2.domain0.imbalance_pct = 125
kernel.sched_domain.cpu2.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu2.domain0.flags = 4655
kernel.sched_domain.cpu2.domain0.name = MC
kernel.sched_domain.cpu3.domain0.min_interval = 1
kernel.sched_domain.cpu3.domain0.max_interval = 4
kernel.sched_domain.cpu3.domain0.busy_idx = 2
kernel.sched_domain.cpu3.domain0.idle_idx = 0
kernel.sched_domain.cpu3.domain0.newidle_idx = 0
kernel.sched_domain.cpu3.domain0.wake_idx = 0
kernel.sched_domain.cpu3.domain0.forkexec_idx = 0
kernel.sched_domain.cpu3.domain0.busy_factor = 64
kernel.sched_domain.cpu3.domain0.imbalance_pct = 125
kernel.sched_domain.cpu3.domain0.cache_nice_tries = 1
kernel.sched_domain.cpu3.domain0.flags = 4655
kernel.sched_domain.cpu3.domain0.name = MC
kernel.vsyscall64 = 1
kernel.ostype = Linux
kernel.osrelease = 2.6.32-573.22.1.el6.x86_64
kernel.version = #1 SMP Wed Mar 23 03:35:39 UTC 2016
kernel.hostname = ap-uce-uop-mq
kernel.domainname = (none)
kernel.pty.max = 4096
kernel.pty.nr = 1
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
kernel.shmmni = 4096
kernel.shm_rmid_forced = 0
kernel.msgmax = 65536
kernel.msgmni = 15737
kernel.msgmnb = 65536
kernel.sem = 250 32000 32 128
kernel.auto_msgmni = 1
vm.overcommit_memory = 0
vm.panic_on_oom = 0
vm.oom_kill_allocating_task = 0
vm.extfrag_threshold = 500
vm.oom_dump_tasks = 1
vm.would_have_oomkilled = 0
vm.overcommit_ratio = 50
vm.overcommit_kbytes = 0
vm.page-cluster = 3
vm.dirty_background_ratio = 10
vm.dirty_background_bytes = 0
vm.dirty_ratio = 20
vm.dirty_bytes = 0
vm.dirty_writeback_centisecs = 500
vm.dirty_expire_centisecs = 3000
vm.nr_pdflush_threads = 0
vm.swappiness = 0
vm.nr_hugepages = 0
vm.nr_hugepages_mempolicy = 0
vm.hugetlb_shm_group = 0
vm.hugepages_treat_as_movable = 0
vm.nr_overcommit_hugepages = 0
vm.lowmem_reserve_ratio = 256 256 32
vm.drop_caches = 0
vm.min_free_kbytes = 67584
vm.extra_free_kbytes = 0
vm.unmap_area_factor = 0
vm.meminfo_legacy_layout = 1
vm.percpu_pagelist_fraction = 0
vm.max_map_count = 65530
vm.laptop_mode = 0
vm.block_dump = 0
vm.vfs_cache_pressure = 100
vm.legacy_va_layout = 0
vm.zone_reclaim_mode = 0
vm.min_unmapped_ratio = 1
vm.min_slab_ratio = 5
vm.stat_interval = 1
vm.mmap_min_addr = 4096
vm.numa_zonelist_order = default
vm.scan_unevictable_pages = 0
vm.memory_failure_early_kill = 0
vm.memory_failure_recovery = 1
vm.admin_reserve_kbytes = 8192
fs.inode-nr = 43147 2072
fs.inode-state = 43147 2072 0 0 0 0 0
fs.file-nr = 736 0 798336
fs.file-max = 798336
fs.nr_open = 1048576
fs.dentry-state = 43591 37426 45 0 0 0
fs.overflowuid = 65534
fs.overflowgid = 65534
fs.leases-enable = 1
fs.dir-notify-enable = 1
fs.lease-break-time = 45
fs.aio-nr = 0
fs.aio-max-nr = 65536
fs.inotify.max_user_instances = 128
fs.inotify.max_user_watches = 8192
fs.inotify.max_queued_events = 16384
fs.epoll.max_user_watches = 1646346
fs.suid_dumpable = 0
fs.binfmt_misc.status = enabled
fs.quota.lookups = 0
fs.quota.drops = 0
fs.quota.reads = 0
fs.quota.writes = 0
fs.quota.cache_hits = 0
fs.quota.allocated_dquots = 0
fs.quota.free_dquots = 0
fs.quota.syncs = 2
fs.quota.warnings = 1
fs.mqueue.queues_max = 256
fs.mqueue.msg_max = 10
fs.mqueue.msgsize_max = 8192
fs.mqueue.msg_default = 10
fs.mqueue.msgsize_default = 8192
fs.nfs.nlm_grace_period = 0
fs.nfs.nlm_timeout = 10
fs.nfs.nlm_udpport = 0
fs.nfs.nlm_tcpport = 0
fs.nfs.nsm_use_hostnames = 0
fs.nfs.nsm_local_state = 0
fs.nfs.nfs_callback_tcpport = 0
fs.nfs.idmap_cache_timeout = 600
fs.nfs.nfs_mountpoint_timeout = 500
fs.nfs.nfs_congestion_kb = 90816
debug.exception-trace = 1
debug.kprobes-optimization = 1
dev.scsi.logging_level = 0
dev.raid.speed_limit_min = 1000
dev.raid.speed_limit_max = 200000
dev.hpet.max-user-freq = 64
dev.mac_hid.mouse_button_emulation = 0
dev.mac_hid.mouse_button2_keycode = 97
dev.mac_hid.mouse_button3_keycode = 100
dev.cdrom.info = CD-ROM information, Id: cdrom.c 3.20 2003/12/17
dev.cdrom.info =
dev.cdrom.info = drive name: sr0
dev.cdrom.info = drive speed: 4
dev.cdrom.info = drive # of slots: 1
dev.cdrom.info = Can close tray: 1
dev.cdrom.info = Can open tray: 1
dev.cdrom.info = Can lock tray: 1
dev.cdrom.info = Can change speed: 1
dev.cdrom.info = Can select disk: 0
dev.cdrom.info = Can read multisession: 1
dev.cdrom.info = Can read MCN: 1
dev.cdrom.info = Reports media changed: 1
dev.cdrom.info = Can play audio: 1
dev.cdrom.info = Can write CD-R: 0
dev.cdrom.info = Can write CD-RW: 0
dev.cdrom.info = Can read DVD: 1
dev.cdrom.info = Can write DVD-R: 0
dev.cdrom.info = Can write DVD-RAM: 0
dev.cdrom.info = Can read MRW: 1
dev.cdrom.info = Can write MRW: 1
dev.cdrom.info = Can write RAM: 1
dev.cdrom.info =
dev.cdrom.info =
dev.cdrom.autoclose = 1
dev.cdrom.autoeject = 0
dev.cdrom.debug = 0
dev.cdrom.lock = 1
dev.cdrom.check_media = 0
net.netfilter.nf_log.0 = NONE
net.netfilter.nf_log.1 = NONE
net.netfilter.nf_log.2 = NONE
net.netfilter.nf_log.3 = NONE
net.netfilter.nf_log.4 = NONE
net.netfilter.nf_log.5 = NONE
net.netfilter.nf_log.6 = NONE
net.netfilter.nf_log.7 = NONE
net.netfilter.nf_log.8 = NONE
net.netfilter.nf_log.9 = NONE
net.netfilter.nf_log.10 = NONE
net.netfilter.nf_log.11 = NONE
net.netfilter.nf_log.12 = NONE
net.core.somaxconn = 128
net.core.xfrm_aevent_etime = 10
net.core.xfrm_aevent_rseqth = 2
net.core.xfrm_larval_drop = 1
net.core.xfrm_acq_expires = 30
net.core.wmem_max = 124928
net.core.rmem_max = 124928
net.core.wmem_default = 124928
net.core.rmem_default = 124928
net.core.dev_weight = 64
net.core.netdev_max_backlog = 1000
net.core.netdev_rss_key = 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
net.core.message_cost = 5
net.core.message_burst = 10
net.core.optmem_max = 20480
net.core.rps_sock_flow_entries = 0
net.core.busy_poll = 0
net.core.busy_read = 0
net.core.netdev_budget = 300
net.core.warnings = 1
net.ipv4.route.gc_thresh = 262144
net.ipv4.route.max_size = 4194304
net.ipv4.route.gc_min_interval = 0
net.ipv4.route.gc_min_interval_ms = 500
net.ipv4.route.gc_timeout = 300
net.ipv4.route.gc_interval = 60
net.ipv4.route.redirect_load = 20
net.ipv4.route.redirect_number = 9
net.ipv4.route.redirect_silence = 20480
net.ipv4.route.error_cost = 1000
net.ipv4.route.error_burst = 5000
net.ipv4.route.gc_elasticity = 8
net.ipv4.route.mtu_expires = 600
net.ipv4.route.min_pmtu = 552
net.ipv4.route.min_adv_mss = 256
net.ipv4.route.secret_interval = 600
net.ipv4.neigh.default.mcast_solicit = 3
net.ipv4.neigh.default.ucast_solicit = 3
net.ipv4.neigh.default.app_solicit = 0
net.ipv4.neigh.default.retrans_time = 99
net.ipv4.neigh.default.base_reachable_time = 30
net.ipv4.neigh.default.delay_first_probe_time = 5
net.ipv4.neigh.default.gc_stale_time = 120
net.ipv4.neigh.default.unres_qlen = 3
net.ipv4.neigh.default.proxy_qlen = 64
net.ipv4.neigh.default.anycast_delay = 99
net.ipv4.neigh.default.proxy_delay = 79
net.ipv4.neigh.default.locktime = 99
net.ipv4.neigh.default.retrans_time_ms = 1000
net.ipv4.neigh.default.base_reachable_time_ms = 30000
net.ipv4.neigh.default.gc_interval = 30
net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024
net.ipv4.neigh.lo.mcast_solicit = 3
net.ipv4.neigh.lo.ucast_solicit = 3
net.ipv4.neigh.lo.app_solicit = 0
net.ipv4.neigh.lo.retrans_time = 99
net.ipv4.neigh.lo.base_reachable_time = 30
net.ipv4.neigh.lo.delay_first_probe_time = 5
net.ipv4.neigh.lo.gc_stale_time = 60
net.ipv4.neigh.lo.unres_qlen = 3
net.ipv4.neigh.lo.proxy_qlen = 64
net.ipv4.neigh.lo.anycast_delay = 99
net.ipv4.neigh.lo.proxy_delay = 79
net.ipv4.neigh.lo.locktime = 99
net.ipv4.neigh.lo.retrans_time_ms = 1000
net.ipv4.neigh.lo.base_reachable_time_ms = 30000
net.ipv4.neigh.eth0.mcast_solicit = 3
net.ipv4.neigh.eth0.ucast_solicit = 3
net.ipv4.neigh.eth0.app_solicit = 0
net.ipv4.neigh.eth0.retrans_time = 99
net.ipv4.neigh.eth0.base_reachable_time = 30
net.ipv4.neigh.eth0.delay_first_probe_time = 5
net.ipv4.neigh.eth0.gc_stale_time = 120
net.ipv4.neigh.eth0.unres_qlen = 3
net.ipv4.neigh.eth0.proxy_qlen = 64
net.ipv4.neigh.eth0.anycast_delay = 99
net.ipv4.neigh.eth0.proxy_delay = 79
net.ipv4.neigh.eth0.locktime = 99
net.ipv4.neigh.eth0.retrans_time_ms = 1000
net.ipv4.neigh.eth0.base_reachable_time_ms = 30000
net.ipv4.tcp_timestamps = 1
缺省值为1
Timestamps 用在其它一些东西中﹐可以防范那些伪造的 sequence 号码。一条1G的宽带线路或许会重遇到带 out-of-line数值的旧sequence 号码(假如它是由于上次产生的)。Timestamp 会让它知道这是个 '旧封包'。(该文件表示是否启用以一种比超时重发更精确的方法（RFC 1323）来启用对 RTT 的计算；为了实现更好的性能应该启用这个选项。)
net.ipv4.tcp_window_scaling = 1
缺省值为1
该文件表示设置tcp/ip会话的滑动窗口大小是否可变。参数值为布尔值，为1时表示可变，为0时表示不可变。tcp/ip通常使用的窗口最大可达到 65535 字节，对于高速网络，该值可能太小，这时候如果启用了该功能，可以使tcp/ip滑动窗口大小增大数个数量级，从而提高数据传输的能力(RFC 1323)。（对普通地百M网络而言，关闭会降低开销，所以如果不是高速网络，可以考虑设置为0）
net.ipv4.tcp_sack = 1
缺省值为1
使用 Selective ACK﹐它可以用来查找特定的遗失的数据报--- 因此有助于快速恢复状态。该文件表示是否启用有选择的应答（Selective Acknowledgment），这可以通过有选择地应答乱序接收到的报文来提高性能（这样可以让发送者只发送丢失的报文段）。(对于广域网通信来说这个选项应该启用，但是这会增加对 CPU 的占用。)
net.ipv4.tcp_retrans_collapse = 1
缺省值为1
对于某些有bug的打印机提供针对其bug的兼容性。(一般不需要这个支持,可以关闭它)
net.ipv4.ip_default_ttl = 64
net.ipv4.ip_nonlocal_bind = 0
net.ipv4.tcp_syn_retries = 5
对于一个新建连接，内核要发送多少个 SYN 连接请求才决定放弃。不应该大于255，默认值是5，对应于180秒左右时间。(对于大负载而物理通信良好的网络而言,这个值偏高,可修改为2.这个值仅仅是针对对外的连接,对进来的连接,是由tcp_retries1 决定的)
net.ipv4.tcp_synack_retries = 2
对于远端的连接请求SYN，内核会发送SYN ＋ ACK数据报，以确认收到上一个 SYN连接请求包。这是所谓的三次握手( threeway handshake)机制的第二个步骤。这里决定内核在放弃连接之前所送出的 SYN+ACK 数目。不应该大于255，默认值是5，对应于180秒左右时间。(可以根据上面的tcp_syn_retries来决定这个值)
net.ipv4.tcp_max_orphans = 262144
缺省值是8192
系统所能处理不属于任何进程的TCP sockets最大数量。假如超过这个数量﹐那么不属于任何进程的连接会被立即reset，并同时显示警告信息。之所以要设定这个限制﹐纯粹为了抵御那些简单的 DoS 攻击﹐千万不要依赖这个或是人为的降低这个限制(这个值Redhat AS版本中设置为32768,但是很多防火墙修改的时候,建议该值修改为2000)
net.ipv4.tcp_max_tw_buckets = 5000
默认值是180000
系统在同时所处理的最大 timewait sockets 数目。如果超过此数的话﹐time-wait socket 会被立即砍除并且显示警告信息。之所以要设定这个限制﹐纯粹为了抵御那些简单的 DoS 攻击﹐千万不要人为的降低这个限制﹐不过﹐如果网络条件需要比默认值更多﹐则可以提高它(或许还要增加内存)。(事实上做NAT的时候最好可以适当地增加该值)
net.ipv4.ip_dynaddr = 0
net.ipv4.tcp_keepalive_time = 7200
当keepalive打开的情况下，TCP发送keepalive消息的频率。(由于目前网络攻击等因素,造成了利用这个进行的攻击很频繁,曾经也有cu的朋友提到过,说如果2边建立了连接,然后不发送任何数据或者rst/fin消息,那么持续的时间是不是就是2小时,空连接攻击?tcp_keepalive_time就是预防此情形的.我个人在做nat服务的时候的修改值为1800秒)
net.ipv4.tcp_keepalive_probes = 9
TCP发送keepalive探测以确定该连接已经断开的次数。(注意:保持连接仅在SO_KEEPALIVE套接字选项被打开是才发送.次数默认不需要修改,当然根据情形也可以适当地缩短此值.设置为5比较合适)
net.ipv4.tcp_keepalive_intvl = 75
探测消息发送的频率，乘以tcp_keepalive_probes就得到对于从开始探测以来没有响应的连接杀除的时间。默认值为75秒，也就是没有活动的连接将在大约11分钟以后将被丢弃。(对于普通应用来说,这个值有一些偏大,可以根据需要改小.特别是web类服务器需要改小该值,15是个比较合适的值)
net.ipv4.tcp_retries1 = 3
放弃回应一个TCP连接请求前﹐需要进行多少次重试。RFC 规定最低的数值是3﹐这也是默认值﹐根据RTO的值大约在3秒 - 8分钟之间。(注意:这个值同时还决定进入的syn连接)
net.ipv4.tcp_retries2 = 15
在丢弃激活(已建立通讯状况)的TCP连接之前﹐需要进行多少次重试。默认值为15，根据RTO的值来决定，相当于13-30分钟(RFC1122规定，必须大于100秒).(这个值根据目前的网络设置,可以适当地改小,我的网络内修改为了5)
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_syncookies = 1
默认值是0
只有在内核编译时选择了CONFIG_SYNCOOKIES时才会发生作用。当出现syn等候队列出现溢出时象对方发送syncookies。目的是为了防止syn flood攻击。
注意：该选项千万不能用于那些没有收到攻击的高负载服务器，如果在日志中出现synflood消息，但是调查发现没有收到synflood攻击，而是合法用户的连接负载过高的原因，你应该调整其它参数来提高服务器性能。参考:
tcp_max_syn_backlog
tcp_synack_retries
tcp_abort_on_overflow
syncookie严重的违背TCP协议，不允许使用TCP扩展，可能对某些服务导致严重的性能影响(如SMTP转发)。(注意,该实现与BSD上面使用的tcp proxy一样,是违反了RFC中关于tcp连接的三次握手实现的,但是对于防御syn-flood的确很有用.)
net.ipv4.tcp_tw_recycle = 0
默认值是0
打开快速 TIME-WAIT sockets 回收。除非得到技术专家的建议或要求﹐请不要随意修改这个值。(做NAT的时候，建议打开它)
net.ipv4.tcp_abort_on_overflow = 0
缺省值是0
当守护进程太忙而不能接受新的连接，就象对方发送reset消息，默认值是false。这意味着当溢出的原因是因为一个偶然的猝发，那么连接将恢复状态。只有在你确信守护进程真的不能完成连接请求时才打开该选项，该选项会影响客户的使用。(对待已经满载的sendmail,apache这类服务的时候,这个可以很快让客户端终止连接,可以给予服务程序处理已有连接的缓冲机会,所以很多防火墙上推荐打开它)
net.ipv4.tcp_stdurg = 0
默认值为0
使用 TCP urg pointer 字段中的主机请求解释功能。大部份的主机都使用老旧的 BSD解释，因此如果您在 Linux 打开它﹐或会导致不能和它们正确沟通。
net.ipv4.tcp_rfc1337 = 0
缺省值为0
这个开关可以启动对于在RFC1337中描述的"tcp 的time-wait暗杀危机"问题的修复。启用后，内核将丢弃那些发往time-wait状态TCP套接字的RST 包.
net.ipv4.tcp_max_syn_backlog = 1024
对于那些依然还未获得客户端确认的连接请求﹐需要保存在队列中最大数目。对于超过 128Mb 内存的系统﹐默认值是1024 ﹐低于 128Mb 的则为 128。如果服务器经常出现过载﹐可以尝试增加这个数字。警告﹗假如您将此值设为大于1024﹐最好修改 include/net/tcp.h 里面的 TCP_SYNQ_HSIZE ﹐以保持TCP_SYNQ_HSIZE*16<=tcp_max_syn_backlog ﹐并且编进核心之内。(SYN Flood攻击利用TCP协议散布握手的缺陷，伪造虚假源IP地址发送大量TCP-SYN半打开连接到目标系统，最终导致目标系统Socket队列资源耗尽而无法接受新的连接。为了应付这种攻击，现代Unix系统中普遍采用多连接队列处理的方式来缓冲(而不是解决)这种攻击，是用一个基本队列处理正常的完全连接应用(Connect()和Accept() )，是用另一个队列单独存放半打开连接。这种双队列处理方式和其他一些系统内核措施(例如Syn-Cookies/Caches)联合应用时，能够比较有效的缓解小规模的SYN Flood攻击(事实证明<1000p/s)加大SYN队列长度可以容纳更多等待连接的网络连接数，所以对Server来说可以考虑增大该值.)
net.ipv4.ip_local_port_range = 32768 61000
net.ipv4.ip_local_reserved_ports =
net.ipv4.igmp_max_memberships = 20
net.ipv4.igmp_max_msf = 10
net.ipv4.inet_peer_threshold = 65664
net.ipv4.inet_peer_minttl = 120
net.ipv4.inet_peer_maxttl = 600
net.ipv4.inet_peer_gc_mintime = 10
net.ipv4.inet_peer_gc_maxtime = 120
net.ipv4.tcp_orphan_retries = 0
在近端丢弃TCP连接之前﹐要进行多少次重试。默认值是7个﹐相当于 50秒 - 16分钟﹐视 RTO 而定。如果您的系统是负载很大的web服务器﹐那么也许需要降低该值﹐这类 sockets 可能会耗费大量的资源。另外参的考tcp_max_orphans 。(事实上做NAT的时候,降低该值也是好处显著的,我本人的网络环境中降低该值为3)
net.ipv4.tcp_fack = 1
缺省值为1
打开FACK拥塞避免和快速重传功能。(注意，当tcp_sack设置为0的时候，这个值即使设置为1也无效)
net.ipv4.tcp_reordering = 3
默认值是3
TCP流中重排序的数据报最大数量 。 (一般有看到推荐把这个数值略微调整大一些,比如5)
net.ipv4.tcp_ecn = 2
缺省值为0
打开TCP的直接拥塞通告功能。
net.ipv4.tcp_dsack = 1
缺省值为1
允许TCP发送"两个完全相同"的SACK。
net.ipv4.tcp_mem = 753600 1004800 1507200
tcp_mem(3个INTEGER变量)：low, pressure, high
low：当TCP使用了低于该值的内存页面数时，TCP不会考虑释放内存。(理想情况下，这个值应与指定给 tcp_wmem 的第 2 个值相匹配 - 这第 2 个值表明，最大页面大小乘以最大并发请求数除以页大小 (131072 * 300 / 4096)。 )
pressure：当TCP使用了超过该值的内存页面数量时，TCP试图稳定其内存使用，进入pressure模式，当内存消耗低于low值时则退出pressure状态。(理想情况下这个值应该是 TCP 可以使用的总缓冲区大小的最大值 (204800 * 300 / 4096)。 )
high：允许所有tcp sockets用于排队缓冲数据报的页面量。(如果超过这个值，TCP 连接将被拒绝，这就是为什么不要令其过于保守 (512000 * 300 / 4096) 的原因了。 在这种情况下，提供的价值很大，它能处理很多连接，是所预期的 2.5 倍；或者使现有连接能够传输 2.5 倍的数据。 我的网络里为192000 300000 732000)
一般情况下这些值是在系统启动时根据系统内存数量计算得到的。
net.ipv4.tcp_wmem = 4096 16384 4194304
tcp_wmem(3个INTEGER变量)： min, default, max
min：为TCP socket预留用于发送缓冲的内存最小值。每个tcp socket都可以在建议以后都可以使用它。默认值为4096(4K)。
default：为TCP socket预留用于发送缓冲的内存数量，默认情况下该值会影响其它协议使用的net.core.wmem_default 值，一般要低于net.core.wmem_default的值。默认值为16384(16K)。
max: 用于TCP socket发送缓冲的内存最大值。该值不会影响net.core.wmem_max，"静态"选择参数SO_SNDBUF则不受该值影响。默认值为131072(128K)。（对于服务器而言，增加这个参数的值对于发送数据很有帮助,在我的网络环境中,修改为了51200 131072 204800）
net.ipv4.tcp_rmem = 4096 87380 4194304
cp_rmem (3个INTEGER变量)： min, default, max
min：为TCP socket预留用于接收缓冲的内存数量，即使在内存出现紧张情况下tcp socket都至少会有这么多数量的内存用于接收缓冲，默认值为8K。
default：为TCP socket预留用于接收缓冲的内存数量，默认情况下该值影响其它协议使用的net.core.wmem_default 值。该值决定了在tcp_adv_win_scale、tcp_app_win和tcp_app_win=0默认值情况下，TCP窗口大小为65535。默认值为87380
max：用于TCP socket接收缓冲的内存最大值。该值不会影响 net.core.wmem_max，"静态"选择参数 SO_SNDBUF则不受该值影响。默认值为 128K。默认值为87380*2 bytes。（可以看出，.max的设置最好是default的两倍,对于NAT来说主要该增加它,我的网络里为 51200 131072 204800）
net.ipv4.tcp_app_win = 31
默认值是31
保留max(window/2^tcp_app_win, mss)数量的窗口由于应用缓冲。当为0时表示不需要缓冲。
net.ipv4.tcp_adv_win_scale = 2
默认值为2
计算缓冲开销bytes/2^tcp_adv_win_scale(如果tcp_adv_win_scale > 0)或者bytes-bytes/2^(-tcp_adv_win_scale)(如果tcp_adv_win_scale <= 0）。
net.ipv4.tcp_tw_reuse = 0
默认值是0
该文件表示是否允许重新应用处于TIME-WAIT状态的socket用于新的TCP连接(这个对快速重启动某些服务,而启动后提示端口已经被使用的情形非常有帮助)
net.ipv4.tcp_frto = 2
net.ipv4.tcp_frto_response = 0
net.ipv4.tcp_low_latency = 0
缺省值为0
允许 TCP/IP 栈适应在高吞吐量情况下低延时的情况；这个选项一般情形是的禁用。(但在构建Beowulf 集群的时候,打开它很有帮助)
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_abc = 0
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_base_mss = 512
net.ipv4.tcp_workaround_signed_windows = 0
net.ipv4.tcp_challenge_ack_limit = 100
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_dma_copybreak = 4096
net.ipv4.tcp_slow_start_after_idle = 1
net.ipv4.cipso_cache_enable = 1
net.ipv4.cipso_cache_bucket_size = 10
net.ipv4.cipso_rbm_optfmt = 0
net.ipv4.cipso_rbm_strictvalid = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_max_ssthresh = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.udp_mem = 753600 1004800 1507200
net.ipv4.udp_rmem_min = 4096
net.ipv4.udp_wmem_min = 4096
net.ipv4.conf.all.forwarding = 0
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.all.secure_redirects = 1
net.ipv4.conf.all.shared_media = 1
net.ipv4.conf.all.rp_filter = 0
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.all.src_valid_mark = 0
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.medium_id = 0
net.ipv4.conf.all.bootp_relay = 0
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.all.tag = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.all.arp_notify = 0
net.ipv4.conf.all.proxy_arp_pvlan = 0
net.ipv4.conf.all.disable_xfrm = 0
net.ipv4.conf.all.disable_policy = 0
net.ipv4.conf.all.force_igmp_version = 0
net.ipv4.conf.all.promote_secondaries = 0
net.ipv4.conf.all.accept_local = 0
net.ipv4.conf.all.route_localnet = 0
net.ipv4.conf.default.forwarding = 0
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.default.accept_redirects = 1
net.ipv4.conf.default.secure_redirects = 1
net.ipv4.conf.default.shared_media = 1
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.src_valid_mark = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.default.medium_id = 0
net.ipv4.conf.default.bootp_relay = 0
net.ipv4.conf.default.log_martians = 0
net.ipv4.conf.default.tag = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.default.arp_notify = 0
net.ipv4.conf.default.proxy_arp_pvlan = 0
net.ipv4.conf.default.disable_xfrm = 0
net.ipv4.conf.default.disable_policy = 0
net.ipv4.conf.default.force_igmp_version = 0
net.ipv4.conf.default.promote_secondaries = 0
net.ipv4.conf.default.accept_local = 0
net.ipv4.conf.default.route_localnet = 0
net.ipv4.conf.lo.forwarding = 0
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.lo.accept_redirects = 1
net.ipv4.conf.lo.secure_redirects = 1
net.ipv4.conf.lo.shared_media = 1
net.ipv4.conf.lo.rp_filter = 0
net.ipv4.conf.lo.send_redirects = 1
net.ipv4.conf.lo.accept_source_route = 1
net.ipv4.conf.lo.src_valid_mark = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.lo.medium_id = 0
net.ipv4.conf.lo.bootp_relay = 0
net.ipv4.conf.lo.log_martians = 0
net.ipv4.conf.lo.tag = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.lo.arp_notify = 0
net.ipv4.conf.lo.proxy_arp_pvlan = 0
net.ipv4.conf.lo.disable_xfrm = 1
net.ipv4.conf.lo.disable_policy = 1
net.ipv4.conf.lo.force_igmp_version = 0
net.ipv4.conf.lo.promote_secondaries = 0
net.ipv4.conf.lo.accept_local = 0
net.ipv4.conf.lo.route_localnet = 0
net.ipv4.conf.eth0.forwarding = 0
net.ipv4.conf.eth0.mc_forwarding = 0
net.ipv4.conf.eth0.accept_redirects = 1
net.ipv4.conf.eth0.secure_redirects = 1
net.ipv4.conf.eth0.shared_media = 1
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.eth0.send_redirects = 1
net.ipv4.conf.eth0.accept_source_route = 0
net.ipv4.conf.eth0.src_valid_mark = 0
net.ipv4.conf.eth0.proxy_arp = 0
net.ipv4.conf.eth0.medium_id = 0
net.ipv4.conf.eth0.bootp_relay = 0
net.ipv4.conf.eth0.log_martians = 0
net.ipv4.conf.eth0.tag = 0
net.ipv4.conf.eth0.arp_filter = 0
net.ipv4.conf.eth0.arp_announce = 2
net.ipv4.conf.eth0.arp_ignore = 0
net.ipv4.conf.eth0.arp_accept = 0
net.ipv4.conf.eth0.arp_notify = 0
net.ipv4.conf.eth0.proxy_arp_pvlan = 0
net.ipv4.conf.eth0.disable_xfrm = 0
net.ipv4.conf.eth0.disable_policy = 0
net.ipv4.conf.eth0.force_igmp_version = 0
net.ipv4.conf.eth0.promote_secondaries = 0
net.ipv4.conf.eth0.accept_local = 0
net.ipv4.conf.eth0.route_localnet = 0
net.ipv4.ip_forward = 0
net.ipv4.xfrm4_gc_thresh = 2097152
net.ipv4.ipfrag_high_thresh = 4194304
net.ipv4.ipfrag_low_thresh = 3145728
net.ipv4.ipfrag_time = 30
net.ipv4.icmp_echo_ignore_all = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.icmp_errors_use_inbound_ifaddr = 0
net.ipv4.icmp_ratelimit = 1000
net.ipv4.icmp_ratemask = 6168
net.ipv4.rt_cache_rebuild_count = 4
net.ipv4.ping_group_range = 1 0
net.ipv4.ip_no_pmtu_disc = 0
net.ipv4.ip_forward_use_pmtu = 0
net.ipv4.ipfrag_secret_interval = 600
net.ipv4.ipfrag_max_dist = 64
net.unix.max_dgram_qlen = 10
abi.vsyscall32 = 1
crypto.fips_enabled = 0
sunrpc.rpc_debug = 0
sunrpc.nfs_debug = 0
sunrpc.nfsd_debug = 0
sunrpc.nlm_debug = 0
sunrpc.transports = tcp 1048576
sunrpc.transports = udp 32768
sunrpc.transports = tcp-bc 1048576
sunrpc.udp_slot_table_entries = 16
sunrpc.tcp_slot_table_entries = 2
sunrpc.tcp_max_slot_table_entries = 65536
sunrpc.min_resvport = 665
sunrpc.max_resvport = 1023
sunrpc.tcp_fin_timeout = 15
默认值是 60
对于本端断开的socket连接，TCP保持在FIN-WAIT-2状态的时间。对方可能会断开连接或一直不结束连接或不可预料的进程死亡。默认值为 60 秒。过去在2.2版本的内核中是 180 秒。您可以设置该值﹐但需要注意﹐如果您的机器为负载很重的web服务器﹐您可能要冒内存被大量无效数据报填满的风险﹐FIN-WAIT-2 sockets 的危险性低于 FIN-WAIT-1 ﹐因为它们最多只吃 1.5K 的内存﹐但是它们存在时间更长。另外参考 tcp_max_orphans。(事实上做NAT的时候,降低该值也是好处显著的,我本人的网络环境中降低该值为30)
