Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757515AbbGQL4W (ORCPT ); Fri, 17 Jul 2015 07:56:22 -0400 Received: from casper.infradead.org ([85.118.1.10]:48985 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752654AbbGQL4U (ORCPT ); Fri, 17 Jul 2015 07:56:20 -0400 Date: Fri, 17 Jul 2015 13:56:15 +0200 From: Peter Zijlstra To: "Wangnan (F)" Cc: kaixu xia , ast@plumgrid.com, davem@davemloft.net, acme@kernel.org, mingo@redhat.com, masami.hiramatsu.pt@hitachi.com, jolsa@kernel.org, linux-kernel@vger.kernel.org, pi3orama@163.com, hekuang@huawei.com Subject: Re: [RFC PATCH 5/6] bpf: Implement function bpf_read_pmu() that get the selected hardware PMU conuter Message-ID: <20150717115615.GA18673@twins.programming.kicks-ass.net> References: <1437129816-13176-1-git-send-email-xiakaixu@huawei.com> <1437129816-13176-6-git-send-email-xiakaixu@huawei.com> <20150717110541.GJ12596@twins.programming.kicks-ass.net> <55A8E703.70306@huawei.com> <20150717113924.GD19282@twins.programming.kicks-ass.net> <55A8EABE.1060308@huawei.com> <20150717115505.GF19282@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150717115505.GF19282@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1055 Lines: 24 On Fri, Jul 17, 2015 at 01:55:05PM +0200, Peter Zijlstra wrote: > On Fri, Jul 17, 2015 at 07:45:02PM +0800, Wangnan (F) wrote: > > > >Depends on what all you need, if you need full perf events to work then > > >yes perf_event_read_value() is your only option. > > > > > >But note that that requires scheduling, so you cannot actually use it > > >for tracing purposes etc.. > > > What you mean "full perf events"? Even with your code some event still not > > work? > > The code I posted only works for events that do not have inherit set. > And only works from IRQ/NMI context for events that monitor the current > task or the current CPU (although that needs a little extra code still). > > Anything else and it does not work (correctly). Scratch that from NMI, for that to work we need more magic still. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/