Date: Sun, 25 Jul 1999 00:10:33 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: aron@cs.rice.edu (Mohit Aron) Cc: freebsd-net@FreeBSD.ORG Subject: Re: FreeBSD tuning for webserver performance Message-ID: <199907242210.AAA01871@labinfo.iet.unipi.it> In-Reply-To: <199907242205.RAA03294@cs.rice.edu> from "Mohit Aron" at Jul 24, 99 05:05:22 pm
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> Hi, > during my work on FreeBSD with Webservers, I've come across several > minor tuning enhancements that need to be applied to the kernel for efficient > performance with Web servers. I'm listing some of them below - perhaps these ... > 2) Increase IP interface queue size (default 50). It can be changed by > recompiling kernel after setting IFQ_MAXLEN in sys/net/if.h. This parameter > determines the max number of packets in a burst that can be handled by the > webserver. A value of 50 is rather small - SYN packets received from > clients connecting simultaneously can overrun the IP queue. I usually > increase this value to 1000. this one i'd be a bit careful about. The same parameter is used for both input (ipqmaxlen = IFQ_MAXLEN) and output queues. On the output side this means you can have up to 1.5MBytes queued on output on one interface -- that's over one second on a 10Mbit ethernet. If you are sending so much data to fill your 50-slot queues (and this can only be because of a burst) you do want drops so that you get immediate feedback and can de-synchronize the flows and avoid further bursts of the same kind. cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) http://www.iet.unipi.it/~luigi/ngc99/ ==== First International Workshop on Networked Group Communication ==== -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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