From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH V2 net] ipv4:correct description for tcp_max_syn_backlog Date: Tue, 6 Dec 2011 09:07:09 -0500 Message-ID: <20111206140709.GA29082@hmsreliant.think-freely.org> References: <4EDDC1D6.6000708@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: shanwei88@gmail.com, Randy Dunlap , "David S. Miller" , Eric Dumazet , Shan Wei , Max Matveev , "open list:DOCUMENTATION" , open list , "open list:NETWORKING [GENERAL]" To: Weiping Pan Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Dec 06, 2011 at 03:39:41PM +0800, Weiping Pan wrote: > 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 are out of date.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 > --- > 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 > > Acked-by: Neil Horman