Since commit c5ed63d66f24(tcp: fix three tcp sysctls tuning), sysctl_max_syn_backlog is determined by tcp_hashinfo->ehash_mask, and the minimal value is 128, and it will increase in proportion to the memory of machine. The original description for tcp_max_syn_backlog and sysctl_max_syn_backlog are out of date. Changelog: V2: update description for sysctl_max_syn_backlog Signed-off-by: Weiping Pan <panweiping3@xxxxxxxxx> --- Documentation/networking/ip-sysctl.txt | 10 +++++----- net/core/request_sock.c | 7 ++++--- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index f049a1c..589f2da 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -282,11 +282,11 @@ tcp_max_ssthresh - INTEGER Default: 0 (off) tcp_max_syn_backlog - INTEGER - Maximal number of remembered connection requests, which are - still did not receive an acknowledgment from connecting client. - Default value is 1024 for systems with more than 128Mb of memory, - and 128 for low memory machines. If server suffers of overload, - try to increase this number. + Maximal number of remembered connection requests, which have not + received an acknowledgment from connecting client. + The minimal value is 128 for low memory machines, and it will + increase in proportion to the memory of machine. + If server suffers from overload, try increasing this number. tcp_max_tw_buckets - INTEGER Maximal number of timewait sockets held by system simultaneously. diff --git a/net/core/request_sock.c b/net/core/request_sock.c index 182236b..9b570a6 100644 --- a/net/core/request_sock.c +++ b/net/core/request_sock.c @@ -26,10 +26,11 @@ * but then some measure against one socket starving all other sockets * would be needed. * - * It was 128 by default. Experiments with real servers show, that + * The minimum value of it is 128. Experiments with real servers show that * it is absolutely not enough even at 100conn/sec. 256 cures most - * of problems. This value is adjusted to 128 for very small machines - * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb). + * of problems. + * This value is adjusted to 128 for low memory machines, + * and it will increase in proportion to the memory of machine. * Note : Dont forget somaxconn that may limit backlog too. */ int sysctl_max_syn_backlog = 256; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
