From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Mc Guire Subject: Re: Kernel config options that impact latency Date: Thu, 4 Jan 2018 19:37:36 +0000 Message-ID: <20180104193736.GA5394@osadl.at> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-rt-users To: "Hindman, Gavin" Return-path: Received: from 178.115.242.59.static.drei.at ([178.115.242.59]:39810 "EHLO mail.osadl.at" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752463AbeADThw (ORCPT ); Thu, 4 Jan 2018 14:37:52 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thu, Jan 04, 2018 at 06:29:37PM +0000, Hindman, Gavin wrote: > Since we seem to be in knowledge-sharing mode, is there an existing list of kernel config parameters, outside of those required to enable preempt_rt, known to impact or improve general system latency? I didn't find anything prowling the various wikis. > Depending on what you mean with general system latency - isolation related config items will allow you to improve the effectiveness of pinning rt tasks to specific cores (e.g. cgroups) further physical isolation like PALLOC (out of tree patch at https://github.com/heechul/palloc) allow reducing cache side-effects and L2/L3 sharing which can be a significant latency source. of course these config items have no effect just by turning them on but they allow to configure system software architectures that are more suitable/robust for mixed rt/non-rt workloads. thx! hofrat