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,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 9482DC433F4 for ; Tue, 28 Aug 2018 12:21:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FA9320898 for ; Tue, 28 Aug 2018 12:21:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FA9320898 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 S1727879AbeH1QMn (ORCPT ); Tue, 28 Aug 2018 12:12:43 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57248 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727085AbeH1QMn (ORCPT ); Tue, 28 Aug 2018 12:12:43 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 79F872634A; Tue, 28 Aug 2018 12:21:18 +0000 (UTC) Received: from krava (unknown [10.43.17.209]) by smtp.corp.redhat.com (Postfix) with SMTP id 35F1B2026D6B; Tue, 28 Aug 2018 12:21:17 +0000 (UTC) Date: Tue, 28 Aug 2018 14:21:16 +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: <20180828122116.GJ23727@krava> References: <6f83f9cd-263e-b073-487f-4c7570105a7d@linux.intel.com> <20180828085703.GG23727@krava> <38f9158b-dca5-2b09-99cb-f12bb62ad5dc@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <38f9158b-dca5-2b09-99cb-f12bb62ad5dc@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 28 Aug 2018 12:21:18 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 28 Aug 2018 12:21:18 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.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 Tue, Aug 28, 2018 at 02:31:04PM +0300, Alexey Budankov wrote: > Hi, > > On 28.08.2018 11:57, Jiri Olsa wrote: > > On Mon, Aug 27, 2018 at 09:16:55PM +0300, Alexey Budankov wrote: > > > > SNIP > > > >> + int trace_fd = rec->session->data->file.fd; > >> + struct aiocb **mmap_aio = rec->evlist->mmap_aio; > >> + int mmap_aio_size = 0; > >> + off_t off; > >> > >> if (!evlist) > >> return 0; > >> @@ -528,14 +632,17 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli > >> if (overwrite && evlist->bkw_mmap_state != BKW_MMAP_DATA_PENDING) > >> return 0; > >> > >> + off = lseek(trace_fd, 0, SEEK_CUR); > >> + > >> for (i = 0; i < evlist->nr_mmaps; i++) { > >> struct auxtrace_mmap *mm = &maps[i].auxtrace_mmap; > >> > >> if (maps[i].base) { > >> - if (perf_mmap__push(&maps[i], rec, record__pushfn) != 0) { > >> - rc = -1; > >> + rc = perf_mmap__push(&maps[i], rec, record__pushfn, &off); > >> + if (rc < 0) > >> goto out; > >> - } > >> + else if (rc > 0) > >> + mmap_aio[mmap_aio_size++] = &maps[i].cblock; > > > > I understand the purpose of mmap_aio array, but I don't see a reason > > to fill it in every time we call record__mmap_read_evlist > > The cycle trips the same number of iterations over kernel buffers > for every call of record__mmap_read_evlist(). Called perf_mmap__push() > checks if there is data ready for spill in the corresponding buffer > and if there is no such data returns 0. So every time we execute > the cycle we get different set of buffers to spill and in this > circumstances dynamic filling of mmap_aio looks preferable. > Lifetime management of perf_mmap object and referenced memory > is not related another thing. argh.. the perf_mmap__push returns 0 for empty buffer, ok jirka