From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 2O7OUDm7UIwL for ; Mon, 25 Mar 2013 11:10:06 +0100 (CET) Received: from mx1.digadd.de (unknown [IPv6:2a01:130:11::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.saout.de (Postfix) with ESMTPS for ; Mon, 25 Mar 2013 11:10:06 +0100 (CET) Message-ID: <51501C0A.5060406@digadd.de> Date: Mon, 25 Mar 2013 10:42:34 +0100 From: Christian Schmidt MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [dm-crypt] kworkers for dm-crypt locked to CPU core 0? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de Cc: linux-kernel@vger.kernel.org Hi everyone, I am trying to troubleshoot some strange performance issues I am seeing on a machine of mine. Said machine had 10 drives mapped via separate dm-crypt instances. The aggregate (read) throughput seems to hover around 120-130MB/s (looking at iostat -x -d) when running an instance of dd if=/dev/dm- of=/dev/null bs=1m for each mapping. However "top" shows that one core is loaded with 99% system tasks, and two to three cores are spinning in iowait. All the kworkers get their share of roughly 10% CPU. "taskset" shows that all of the kworkers have an affinity mask of 1, so they can run on core 0 only, and trying to change it results in an error of "Invalid argument". Is there a way I can make the scheduler put those on multiple cores? Please cc: me since I am not subscribed. Regards, Christian