From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Poehn Subject: [PATCH] Documentation: Mention chunk format for irq affinity Date: Wed, 22 Jul 2015 10:09:36 +0200 Message-ID: <1437552576.2783.19.camel@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:37375 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755889AbbGVIJj (ORCPT ); Wed, 22 Jul 2015 04:09:39 -0400 Received: by wibud3 with SMTP id ud3so159732856wib.0 for ; Wed, 22 Jul 2015 01:09:38 -0700 (PDT) Received: from de-ka-36785.green.sophos ([2001:1a80:2000:2:4637:e6ff:feaa:80c4]) by smtp.googlemail.com with ESMTPSA id da5sm2082405wib.6.2015.07.22.01.09.37 for (version=TLSv1/SSLv3 cipher=OTHER); Wed, 22 Jul 2015 01:09:37 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: It may not be obvious for everyone that bitmasks in proc require 32bit chunking Signed-off-by: Sebastian Poehn --- Documentation/IRQ-affinity.txt | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/IRQ-affinity.txt b/Documentation/IRQ-affinity.txt index 01a6751..d873dab 100644 --- a/Documentation/IRQ-affinity.txt +++ b/Documentation/IRQ-affinity.txt @@ -55,6 +55,11 @@ round-trip min/avg/max = 0.1/0.5/585.4 ms This time around IRQ44 was delivered only to the last four processors. i.e counters for the CPU0-3 did not change. +Note that you have to split the bitmask to chunks when using more that 32 cpus: +[root@moon 44]# echo 80,00000000 > smp_affinity +[root@moon 44]# cat smp_affinity +80,00000000 + Here is an example of limiting that same irq (44) to cpus 1024 to 1031: [root@moon 44]# echo 1024-1031 > smp_affinity_list -- 2.4.3