Re: Tuning Linux for performance

From: Julien VEHENT <>
Date: Wed, 17 Jun 2009 22:12:40 -0400

Hey guys,

I'm very disappointed... I was expecting a passionated exchange on the necessity of this parameter in that environment, something like a thread of 40/50 emails that would have led to a doc somewhere on the internet

But... nothing. Maybe you guys are discussing in private and are going to reveal your secrets as an oreilly book in a week or two ? no ?

OK, seriously, I know willy studied a lot linux optimisation, and apparently there are a bunch of people here who know a lot on the subject... what do you think about sharing that with the padawans ? :)

(stepping back and watching)


Ashwani Wason a écrit :
> Willy,
> In one of the relatively recent posts you mentioned, "The rest is
> "just" kernel parameter tuning. I'm thinking about writing a tuning
> guide for 2.6 kernels. I've once again been contacted by a big site
> this week-end which was dying under load because the sysctls had not
> been tuned, and that's a shame :-/".
> I am wondering if you ever managed to create that guide. I am planning
> to evaluate HAProxy and compare its performance with one of my own TCP
> proxy on Linux. So far for a target benchmark and a prototype (simple
> data copy from clients to the servers and back) I have been able to
> achieve ~800 mbps (reported by application, not including TCP/IP/link
> headers) with a single process (no threads) instance on 2.6.18 on a
> 2.6GHz CPU (machine with four CPUs) and two e1000g NICs (one for
> client and one for server). I have done the usual stuff that I
> required to get this to work (bind the interrupts from NICs to two
> CPUs, bind the process to the third CPU, do TCP tuning like syn
> backlog, tw reuse/recycle/buckets, tcp wmem/rmem, driver tuning such
> as rx rings, etc.) The link is gbps so obviously my expectation is to
> get as close to gbps as possible. Routing tests have shown that I
> should be able to do ~970mbps. However, with two processes I am unable
> to reach that limit. Without going into much details as to what
> exactly is happening (which I don't mind going into if useful), I was
> looking for information on how you are tuning for gigabit links.
> Thanks,
> - Ashwani


Received on 2009/06/18 04:12

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