From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935229AbaH0QDk (ORCPT ); Wed, 27 Aug 2014 12:03:40 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39319 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934967AbaH0QDj (ORCPT ); Wed, 27 Aug 2014 12:03:39 -0400 Date: Wed, 27 Aug 2014 17:03:35 +0100 From: Mel Gorman To: H Peter Anvin , Suresh Siddha Cc: Mike Galbraith , Linux-X86 , LKML Subject: Re: [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches Message-ID: <20140827160335.GD12424@suse.de> References: <1407329748-3928-1-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1407329748-3928-1-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 06, 2014 at 01:55:45PM +0100, Mel Gorman wrote: > Eager FPU switching is used on CPUs that support xsave on the grounds > that CPUs that support it can optimise the switch with xsaveopt and xrstor > instead of serialising by updating cr0.TS which has serialising semantics. > > The path for eagerfpu is fatter than it needs to be because it still > maintains the fpu_counter for lazy FPU switches even though the information > is never used. This patch splits the paths optimises the eagerfpu path a > little. The benefit is marginal, it was just noticed when looking at why > integer-only workloads were spending time saving/restoring FPU states. > This was initially sent when it would collide with the merge window which was stupid timing. Nothing has actually changed since but I wonder if anyone had a chance to take a look at this patches? Thanks -- Mel Gorman SUSE Labs