From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbdLMQPY (ORCPT ); Wed, 13 Dec 2017 11:15:24 -0500 Received: from mail-qt0-f170.google.com ([209.85.216.170]:32826 "EHLO mail-qt0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752860AbdLMQPX (ORCPT ); Wed, 13 Dec 2017 11:15:23 -0500 X-Google-Smtp-Source: ACJfBosGkP5L8VnDwifYoIkE4ojpBS3aPPRUyj8BeUreL5gO4AqxtGvTlkzvA+Zz09fItFFyQnVtgg== Date: Wed, 13 Dec 2017 08:15:19 -0800 From: Tejun Heo To: Jiri Olsa Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [RFC] Sharing PMU counters across compatible events Message-ID: <20171213161519.GU3919388@devbig577.frc2.facebook.com> References: <20171201141950.GB2421075@devbig577.frc2.facebook.com> <20171206114204.GB10580@krava> <20171211153449.GJ2421075@devbig577.frc2.facebook.com> <20171213101807.GA2883@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171213101807.GA2883@krava> 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 Hello, Jiri. On Wed, Dec 13, 2017 at 11:18:07AM +0100, Jiri Olsa wrote: > so I can see this to be useful for HW conters only, because > of limited number of regs > > as for the higher level on which this could be implemented I > see some pitfals with event rotations as Peter mentioned and > task/cpu contexts scheduling.. while the hw-level implementation > seems pretty straight forward Heh, yeah, maybe. > I'll test the code and let's see ;-) Thanks. I'll think more about it and see whether this can be evolved into something useable. Thanks. -- tejun