Re: aio_read implementaion in Squid

Andres Kroonmaa wrote:

> On 13 Sep 2001, at 18:01, Venkatesh <gv_kovai@yahoo.com> wrote:
>
>
>>Thanks for your valuable points. Actually I wanted to start that before 2
>>weeks itself. But As I was busy with other works, I could not make it. Again
>>I am stressing you all that I am for very very very High performance Squid.
>>say It should handle 1k req/sec. I am not really for very quicker solution.
>>So Pls guide me in this way.
>>
>>So my objective will be,
>>* If you want to finish eventio model first, Ie for moderate performance
>>improvement, I can try to contribute from my side.
>>* But Before doing that, I should get fair decision of what I/O will be good
>>for Squid in all aspects to achieve 1k req/sec.
>>
>
> Current squid can easily handle 1k req/sec without disks involved. In last
> days one of our reverse-proxies was handling 540 req/sec with single disk,
> although its memhitrate is at 90-95%...
> Next bottleneck after disks is ACL's. If you use no or very few acls, only
> then comes io model into play.
> And while at that, it makes a huge difference, whether you service alot of
> slow clients or few fast clients. When you have few open sockets, poll model
> is very much okay.

1k reqs/sec? Are you sure? I wouldn't think so, even entirely from
RAM. 500, yes. I've seen that in memory only benchmarks (95% memhits),
but performance starts to degrade when going much above that number (at
least on an 800MHz Athlon--faster machines can obviously go a little
faster). You could gain probably another 50-75% performance using dual
processors...but even so...Once disks become involved things drop way
off. We are definitely hitting CPU performance bottlenecks within
Squid--the disk i/o layer is not the only performance killer, though
definitely a big contributor.

>>I know filesystem also another big bottleneck. Assume now, FileSystem is not
>>bottleneck and tell me How much My squid can handle and with which Net I/O
>>Implementation?
>>
>
> I don't think anyone has any figures or tests done on that matter.

I've done tests of memory only Squid's, but nothing of alternate
networking i/o methods (since Squid only has one really).

I would think TUX is probably a good place to look for network I/O
performance implementation ideas. Almost everything used in TUX has
been brought out to userspace (and the X15 Apache from Chromium, uses
many of those userspace hooks--but commercial use of the source is
prohibited so I haven't taken a look to see just how they're doing it--I
suppose some of the volunteer Squid guys could look at X15 without
violating the intent of the license).

                                   --
                      Joe Cooper <joe@swelltech.com>
                  Affordable Web Caching Proxy Appliances
                         http://www.swelltech.com
Received on Thu Sep 13 2001 - 14:25:12 MDT