I getting lots of these in /var/log/messages:
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kernel: TCP: out of memory -- consider tuning tcp_memCode: Select all
# sysctl net.ipv4.tcp_mem
net.ipv4.tcp_mem = 384027 512036 768054
# sysctl net.ipv4.tcp_rmem
net.ipv4.tcp_rmem = 4096 87380 6291456
# sysctl net.ipv4.tcp_wmem
net.ipv4.tcp_wmem = 4096 16384 4194304
# sysctl net.core.rmem_max
net.core.rmem_max = 212992
# sysctl net.core.wmem_max
net.core.wmem_max = 212992Code: Select all
# uname -a
Linux inf-fw2 4.9.34-gentoo #1 SMP Mon Jul 10 11:05:23 CEST 2017 x86_64 AMD FX(tm)-8320 Eight-Core Processor AuthenticAMD GNU/Linux
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# top
top - 17:51:33 up 19 days, 10:18, 2 users, load average: 1.38, 1.49, 1.42
Tasks: 344 total, 1 running, 343 sleeping, 0 stopped, 0 zombie
%Cpu0 : 2.2 us, 0.5 sy, 0.0 ni, 93.0 id, 0.0 wa, 0.0 hi, 4.3 si, 0.0 st
%Cpu1 : 0.5 us, 0.0 sy, 0.0 ni, 97.9 id, 0.0 wa, 0.0 hi, 1.6 si, 0.0 st
%Cpu2 : 1.1 us, 0.0 sy, 0.5 ni, 95.2 id, 0.0 wa, 0.0 hi, 3.2 si, 0.0 st
%Cpu3 : 1.1 us, 0.5 sy, 0.0 ni, 96.3 id, 0.0 wa, 0.0 hi, 2.1 si, 0.0 st
%Cpu4 : 2.1 us, 0.0 sy, 0.0 ni, 96.3 id, 0.0 wa, 0.0 hi, 1.6 si, 0.0 st
%Cpu5 : 0.5 us, 0.0 sy, 0.0 ni, 98.9 id, 0.0 wa, 0.0 hi, 0.5 si, 0.0 st
%Cpu6 : 0.5 us, 1.1 sy, 0.0 ni, 96.8 id, 0.0 wa, 0.0 hi, 1.6 si, 0.0 st
%Cpu7 : 1.6 us, 0.0 sy, 0.0 ni, 90.9 id, 0.0 wa, 0.0 hi, 7.5 si, 0.0 st
KiB Mem : 32865056 total, 820664 free, 20358972 used, 11685420 buff/cache
KiB Swap: 37036988 total, 34924984 free, 2112004 used. 12014564 avail MemWhat should I do?
A quick search suggests NOT to touch tcp_mem, but increase the other variable values.
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sysctl -w net.core.rmem_max=8738000
sysctl -w net.core.wmem_max=6553600
sysctl -w net.ipv4.tcp_rmem=8192 873800 8738000
sysctl -w net.ipv4.tcp_wmem=4096 655360 6553600
Why aren't the kernel defaults enough?
In any case, how should I calculate my optimum values given my RAM?
Thanks,
Vieri
[EDIT: adding more info]
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# cat /proc/net/sockstat
sockets: used 13121
TCP: inuse 10010 orphan 11 tw 246 alloc 12597 mem 772909
UDP: inuse 92 mem 59
UDPLITE: inuse 0
RAW: inuse 7
FRAG: inuse 0 memory 0
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# cat /proc/net/sockstat6
TCP6: inuse 282
UDP6: inuse 40
UDPLITE6: inuse 0
RAW6: inuse 5
FRAG6: inuse 0 memory 0Code: Select all
# sysctl -a |grep tcp
fs.nfs.nfs_callback_tcpport = 0
fs.nfs.nlm_tcpport = 0
net.ipv4.tcp_abort_on_overflow = 0
net.ipv4.tcp_adv_win_scale = 1
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_app_win = 31
net.ipv4.tcp_autocorking = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_base_mss = 1024
net.ipv4.tcp_challenge_ack_limit = 1000
sysctl: net.ipv4.tcp_congestion_control = cubic
reading key "net.ipv6.conf.all.stable_secret"net.ipv4.tcp_dsack = 1
net.ipv4.tcp_early_retrans = 3
net.ipv4.tcp_ecn = 2
net.ipv4.tcp_ecn_fallback = 1
net.ipv4.tcp_fack = 1
net.ipv4.tcp_fastopen = 1
net.ipv4.tcp_fastopen_key = 6707aeac-2dd079df-0dee3da3-befd1107
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_frto = 2
net.ipv4.tcp_fwmark_accept = 0
net.ipv4.tcp_invalid_ratelimit = 500
net.ipv4.tcp_keepalive_intvl = 75
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_time = 7200
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_low_latency = 0
net.ipv4.tcp_max_orphans = 131072
net.ipv4.tcp_max_reordering = 300
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.tcp_max_tw_buckets = 131072
net.ipv4.tcp_mem = 384027 512036 768054
net.ipv4.tcp_min_rtt_wlen = 300
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_notsent_lowat = -1
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_pacing_ca_ratio = 120
net.ipv4.tcp_pacing_ss_ratio = 200
net.ipv4.tcp_probe_interval = 600
net.ipv4.tcp_probe_threshold = 8
net.ipv4.tcp_recovery = 1
net.ipv4.tcp_reordering = 3
net.ipv4.tcp_retrans_collapse = 1
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_retries2 = 15
net.ipv4.tcp_rfc1337 = 0
net.ipv4.tcp_rmem = 4096 87380 6291456
net.ipv4.tcp_sack = 1
net.ipv4.tcp_slow_start_after_idle = 1
net.ipv4.tcp_stdurg = 0
net.ipv4.tcp_syn_retries = 6
net.ipv4.tcp_synack_retries = 5
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_tw_recycle = 0
net.ipv4.tcp_tw_reuse = 0
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_wmem = 4096 16384 4194304
net.ipv4.tcp_workaround_signed_windows = 0
sysctl: reading key "net.ipv6.conf.default.stable_secret"
sysctl: reading key "net.ipv6.conf.enp10s0.stable_secret"
sysctl: reading key "net.ipv6.conf.enp5s0.stable_secret"
sysctl: reading key "net.ipv6.conf.enp6s0.stable_secret"
sysctl: reading key "net.ipv6.conf.enp7s0f0.stable_secret"
sysctl: reading key "net.ipv6.conf.enp7s0f1.stable_secret"
sysctl: reading key "net.ipv6.conf.enp7s0f2.stable_secret"
sysctl: reading key "net.ipv6.conf.enp7s0f3.stable_secret"
sysctl: reading key "net.ipv6.conf.enp8s5.stable_secret"
sysctl: reading key "net.ipv6.conf.lo.stable_secret"
net.netfilter.nf_conntrack_tcp_be_liberal = 0
net.netfilter.nf_conntrack_tcp_loose = 1
net.netfilter.nf_conntrack_tcp_max_retrans = 3
net.netfilter.nf_conntrack_tcp_timeout_close = 10
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_established = 432000
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_last_ack = 30
net.netfilter.nf_conntrack_tcp_timeout_max_retrans = 300
net.netfilter.nf_conntrack_tcp_timeout_syn_recv = 60
net.netfilter.nf_conntrack_tcp_timeout_syn_sent = 120
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_unacknowledged = 300
