From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2.tohojo.dk (mail2.tohojo.dk [77.235.48.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 476C721F35C for ; Thu, 23 Apr 2015 04:01:11 -0700 (PDT) X-Virus-Scanned: amavisd-new at mail2.tohojo.dk Received: by alrua-kau.kau.toke.dk (Postfix, from userid 1000) id 69B47C40254; Thu, 23 Apr 2015 13:01:03 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toke.dk; s=201310; t=1429786864; bh=YQClVxE0u/fN7jiElWW7PRtyVGYTW/HWjpDYmj0R9Xs=; h=From:To:Cc:Subject:References:Date:In-Reply-To; b=gqhOBcUddZfYviA3BmT9CYESm6CRrGMX3zbTWpIEaT3QX8WW4Ip53uZ6+RIEAfvyK 9SdjVPRf8iRYxfcXBs0w13jRfZPFqbvASC3UhKVlUZ9BtsqfDssrdqqYkmcZ+HgKgt gpZgkMtGXrBeUjYQCiJ8AlM/0rJYXItY+aaCsVhY= From: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= To: Adrian Popescu References: <5BC1CA30-289D-42B4-95CD-3AE5D7B96F09@gmail.com> <87383r9q1u.fsf@toke.dk> Date: Thu, 23 Apr 2015 13:01:03 +0200 In-Reply-To: (Adrian Popescu's message of "Thu, 23 Apr 2015 13:56:42 +0300") X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87lhhj85xs.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] Cake3 - source code and some questions X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Apr 2015 11:01:40 -0000 Adrian Popescu writes: > Thanks to your experiment and your statement regarding CPU load on > your box during testing, I was able to fix the problem. Cool! > It looks like this problem was being caused by power saving. Something > changed between the older kernels and the newer ones. Changing the > power saving settings in the BIOS brings back latency below 0.5 > milliseconds. So is this the PCI bus power saving settings, or the CPU, or? > This might have an impact some benchmarks which don't load up all CPU > cores or which don't need a lot of CPU power. This is certainly > something to keep an eye on when doing any kind of testing involving > really low latencies or network schedulers. Yes, definitely. Having things be worse during idle is definitely not optimal. I wonder if there's a kernel-level setting that can affect this? -Toke