From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: Q: cpuidle results in degredation in ethernet performance ? Date: Tue, 04 Aug 2015 16:28:39 +0200 Message-ID: <55C0CC17.604@linaro.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-wi0-f180.google.com ([209.85.212.180]:33219 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756382AbbHDO2m (ORCPT ); Tue, 4 Aug 2015 10:28:42 -0400 Received: by wijp15 with SMTP id p15so8617547wij.0 for ; Tue, 04 Aug 2015 07:28:41 -0700 (PDT) In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Ran Shalit , linux-pm@vger.kernel.org On 08/01/2015 09:34 PM, Ran Shalit wrote: > Hello, > > Maybe if someone here understands cpuidel he can help me... > > I am using omap, with cpuidel and I have some strange behaviour only > when cpuidle is used: > 1. I test ethernet bandwidth with iperf > 2. With large packet test (16k), I get same bandwidth in version with > cpuidle support as in version without cpuidel supported. > 3. With small packet test (<2000 bytes), I get high degredation in > performance in version with cpuidle. On viewing statistics I see that > the cpu gets into cpu inactive state (C3 state - not retention yet, > only cpu not active). I guess this is the cuase of the degredation. > With large packets I get no increment in C3 state usage. > 4. I think that menu governer behaviour might explain this, but I > don't understand it deeply enough. > > Can anyone shed a light on this ? Is there anything I can do to overc= ome this ? Is an omap3 or omap4 ? --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog