From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBDE0C433F5 for ; Tue, 28 Aug 2018 08:50:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6ED182089F for ; Tue, 28 Aug 2018 08:50:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6ED182089F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727580AbeH1MlD (ORCPT ); Tue, 28 Aug 2018 08:41:03 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49330 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726975AbeH1MlD (ORCPT ); Tue, 28 Aug 2018 08:41:03 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D728A818F04B; Tue, 28 Aug 2018 08:50:24 +0000 (UTC) Received: from krava (unknown [10.43.17.209]) by smtp.corp.redhat.com (Postfix) with SMTP id 8AEDFA9EB1; Tue, 28 Aug 2018 08:50:23 +0000 (UTC) Date: Tue, 28 Aug 2018 10:50:22 +0200 From: Jiri Olsa To: Alexey Budankov Cc: Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , Andi Kleen , linux-kernel Subject: Re: [PATCH v3 2/2]: perf record: enable asynchronous trace writing Message-ID: <20180828085022.GE23727@krava> References: <6f83f9cd-263e-b073-487f-4c7570105a7d@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6f83f9cd-263e-b073-487f-4c7570105a7d@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 28 Aug 2018 08:50:25 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 28 Aug 2018 08:50:25 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jolsa@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 27, 2018 at 09:16:55PM +0300, Alexey Budankov wrote: > > Trace file offset are linearly calculated by perf_mmap__push() code > for the next possible write operation, but file position is updated by > the kernel only in the second lseek() syscall after the loop. > The first lseek() syscall reads that file position for > the next loop iterations. > > record__mmap_read_sync implements sort of a barrier between spilling > ready profiling data to disk. > > Signed-off-by: Alexey Budankov > --- > Changes in v3: > - written comments about nanosleep(0.5ms) call prior aio_suspend() > to cope with intrusiveness of its implementation in glibc; > - written comments about rationale behind coping profiling data > into mmap->data buffer; > --- > tools/perf/builtin-record.c | 125 +++++++++++++++++++++++++++++++++++++++++--- > tools/perf/util/mmap.c | 36 ++++++++----- > tools/perf/util/mmap.h | 2 +- > 3 files changed, 143 insertions(+), 20 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 22ebeb92ac51..4ac61399a09a 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -53,6 +53,7 @@ > #include > #include > #include > +#include > > struct switch_output { > bool enabled; > @@ -121,6 +122,23 @@ static int record__write(struct record *rec, void *bf, size_t size) > return 0; > } > > +static int record__aio_write(int trace_fd, struct aiocb *cblock, > + void *buf, size_t size, off_t off) > +{ > + cblock->aio_fildes = trace_fd; > + cblock->aio_buf = buf; > + cblock->aio_nbytes = size; > + cblock->aio_offset = off; > + cblock->aio_sigevent.sigev_notify = SIGEV_NONE; > + > + if (aio_write(cblock) == -1) { > + pr_err("failed to queue perf data, error: %m\n"); > + return -1; > + } > + > + return 0; > +} > + > static int process_synthesized_event(struct perf_tool *tool, > union perf_event *event, > struct perf_sample *sample __maybe_unused, > @@ -130,12 +148,14 @@ static int process_synthesized_event(struct perf_tool *tool, > return record__write(rec, event, event->header.size); > } > > -static int record__pushfn(void *to, void *bf, size_t size) > +static int record__pushfn(void *to, void *bf, size_t size, off_t off) > { > struct record *rec = to; > + struct perf_mmap *map = bf; the argument needs to change for record__pushfn, now with your changes, it's no longer 'void *bf', but 'struct perf_mmap *map' also I'm little confused why we have '*to' and cast it back to 'struct record', but so be it ;-) thanks, jirka