Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755022AbYKNWkV (ORCPT ); Fri, 14 Nov 2008 17:40:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751505AbYKNWkJ (ORCPT ); Fri, 14 Nov 2008 17:40:09 -0500 Received: from fg-out-1718.google.com ([72.14.220.159]:39010 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751416AbYKNWkH (ORCPT ); Fri, 14 Nov 2008 17:40:07 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=IC7E+t21wV+mJzsbFBnKCkRvCoFlbts1AMPkqR3FfBSkz0TbHU0JQQvMtBjTrqqBim cac/xkpAtqnwwHwW9H15PthUWufOn3rtPc/vNjoUew9DPVRW3SdAV+6Nzkt2c90r2efY 1449R81CJaw/2mdl0qd3g7x/WIwOISaJGs5sc= Message-ID: Date: Fri, 14 Nov 2008 23:40:05 +0100 From: "Olaf van der Spek" To: "Willy Tarreau" Subject: Re: Unix sockets via TCP on localhost: is TCP slower? Cc: "David Miller" , jrm8005@gmail.com, linux-kernel@vger.kernel.org In-Reply-To: <20081114210759.GX24654@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <3aaafc130811131619w3ba48a86u6c6e2af35f149bf1@mail.gmail.com> <20081114.005635.131100777.davem@davemloft.net> <20081114210759.GX24654@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 35 On Fri, Nov 14, 2008 at 10:07 PM, Willy Tarreau wrote: > I'm already wondering what problems you encounter with TCP performance > on the loopback. I'm used to stress-test network proxies on the loopback None. It's just a theoretical question. > for quick tests when I don't want to boot 3 machines, and seeing that it's > easy to connect/accept 100k sessions/s and forward about 20-30 Gbps between > two processes on consumer-grade machines, I'm really doubting that your > applications needs that much out of your database. Hmm, those numbers look a lot better than the ones Chris Friesen posted. He posted 334 mbyte/s for TCP and 1564 for Unix. That's a 4.7x difference. > If you're really so sensible to local traffic tunning, you can already > set a very large MTU on your loopback, you can have very large windows > between your applications so that very few ACKs are sent, etc... And > BTW checksums are already not even computed. Loopback *is* fast, there's That was my initial question. If the performance difference is insignificant, that's fine with me. > no need to crapify the whole stack with your "switch" to gain 5% more out > of it. > > Anyway, if you can come up with patches which proves all of us wrong > without weakening the code, I'm sure they could be accepted. I'm sure too, but I won't. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/