Re: minimal VM usage version of Squid

From: Stewart Forster <>
Date: Tue, 07 Jan 1997 15:49:29 +1100

> After receiving numerous messages about Squid's hunger for memory,
> I spent a couple of days hacking up a version which writes immediately
> to disk. It is probably inefficient to the other extreme--all objects
> are written to disk. Uncachable objects are promptly removed.
> This code seems to have a number of bugs still, but if you want
> to try it out, it can be found at:
> You certainly should not replace your existing squid installations with
> this one. But I'd be interested to hear from people concerning its
> perceived performance. And of course any bug fixes would be wonderful.

Pushing everything out to disk will be slower but not by a large amount.
Using asynch disk I/O will also help heaps there. I've practically finished
debug/testing asynch I/O here at Connect and it is a large performance win
although CPU gets chewed doing frequent polling when requests are outstanding
(roughly 50% - up from 25% using non-async I/O on our boxes).

We found major memory wins by switching malloc libraries. Libc malloc and
GNU malloc simply cannot cope with squid's memory allocation patterns and do
a VERY poor job when memory runs low. We gained a factor of 4 performance
in low memory situations just by changing the malloc library. Unfortunately
the malloc library we used is not in the public domain...


Stewart Forster (Security and Web Proxy Cache Administrator) pty ltd, Level 9, 114 Albert Rd, Sth Melbourne, VIC 3205, Aust.
Email:   Phone: +61 3 9251-3684   Fax: +61 3 9251-3666
Received on Mon Jan 06 1997 - 21:03:36 MST

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