Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934425AbcJUVQ1 (ORCPT ); Fri, 21 Oct 2016 17:16:27 -0400 Received: from mail-it0-f67.google.com ([209.85.214.67]:36346 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932965AbcJUVQY (ORCPT ); Fri, 21 Oct 2016 17:16:24 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 21 Oct 2016 17:16:22 -0400 (EDT) X-X-Sender: vince@macbook-air To: Wang Nan cc: mtk.manpages@gmail.com, pi3orama@163.com, linux-kernel@vger.kernel.org, linux-man@vger.kernel.org, lizefan@huawei.com, vincent.weaver@maine.edu Subject: Re: [PATCH 1/2] perf_event_open.2: Document PERF_EVENT_IOC_PAUSE_OUTPUT In-Reply-To: <1477049893-143199-1-git-send-email-wangnan0@huawei.com> Message-ID: References: <1477049893-143199-1-git-send-email-wangnan0@huawei.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 773 Lines: 24 On Fri, 21 Oct 2016, Wang Nan wrote: > -.SS Using prctl(2) > +.SS Using prctl why this change? > +.BR PERF_EVENT_IOC_PAUSE_OUTPUT " (since Linux 4.7)" > +.\" commit 86e7972f690c1017fd086cdfe53d8524e68c661c > +This allows pausing and resuming the event's ring-buffer. A > +paused ring-buffer does not prevent samples generation, but simply > +discards them. The discarded samples are considered lost, causes > +.BR PERF_RECORD_LOST > +to be generated when possible. I don't know if it's worth mentioning that the reason to add this is to allow reading the ring-buffer without having to worry about data being overwritten. There are a few odd wording choices (mostly plural nouns) but otherwise looks fine to me. Reviewed-by: Vince Weaver