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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 6DEE4C4361B for ; Tue, 15 Dec 2020 19:46:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31B3322B2C for ; Tue, 15 Dec 2020 19:46:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727249AbgLOTqO (ORCPT ); Tue, 15 Dec 2020 14:46:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:53373 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbgLOTpk (ORCPT ); Tue, 15 Dec 2020 14:45:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608061451; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0t2O3F8bzMQmXxHesxjoW/ncuaguOfyCormLfZAXJm4=; b=PfwdAGc5UmuoWvtoWZaOBTGzDjw/h9AUMMNji8a3AL5sTz9rugM1+zrDr4aQhs9jZxUxh8 aktD8cpHPU3k+yh4BR7xffWmYJ/DvvqSpImMbNkO91cyJar/J/Qw8dufsf0zkHDbEeaI/g qXmQcOxN4fIHNkVGOmGpsTmsPG4NMyM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-221-I1k2LmunPNaZ1j-rNeTZ3Q-1; Tue, 15 Dec 2020 14:44:05 -0500 X-MC-Unique: I1k2LmunPNaZ1j-rNeTZ3Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 287B4195D563; Tue, 15 Dec 2020 19:44:03 +0000 (UTC) Received: from krava (ovpn-112-106.ams2.redhat.com [10.36.112.106]) by smtp.corp.redhat.com (Postfix) with SMTP id 37A2B19C47; Tue, 15 Dec 2020 19:43:58 +0000 (UTC) Date: Tue, 15 Dec 2020 20:43:54 +0100 From: Jiri Olsa To: Alexei Budankov Cc: Jiri Olsa , Arnaldo Carvalho de Melo , lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Ian Rogers , Stephane Eranian Subject: Re: [PATCH 4/8] perf daemon: Add daemon command Message-ID: <20201215194354.GH698181@krava> References: <20201212104358.412065-1-jolsa@kernel.org> <20201212104358.412065-5-jolsa@kernel.org> <1e467abe-4613-765f-5138-6215b711f9fb@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1e467abe-4613-765f-5138-6215b711f9fb@huawei.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 15, 2020 at 06:40:26PM +0300, Alexei Budankov wrote: > Hi, > > On 12.12.2020 13:43, Jiri Olsa wrote: > > Adding daemon command that allows to run record sessions > > on background. Each session represents one perf record > > process and is configured in config file. > > > > Example: > > > > # cat config.daemon > > [daemon] > > base=/opt/perfdata > > It could probably make sense to consider using locations at /var/ > directory, similar to other already existing daemon processes in > system so admin and user experience would be easily reusabe for > performance monitoring daemon (service). hm, you can specify any /var path in there if you like, do you suggest to hardcode it? > > > > > [session-1] > > run = -m 10M -e cycles -o /opt/perfdata/1/perf.data --overwrite --switch-output -a > > > > [session-2] > > run = -m 20M -e sched:* -o /opt/perfdata/2/perf.data --overwrite --switch-output -a > > > > Default perf config has the same daemon base: > > > > # cat ~/.perfconfig > > [daemon] > > base=/opt/perfdata > > > > Starting the daemon: > > > > # perf daemon --config config.daemon > > It could make sense to name daemon config file similar to .perfconfig > e.g. like .perfconfig.daemon. perf daemon command would then assume, by > default, usage of .perfconfig.daemon config or the one specified on the > command line via --config option. It also would be helpfull have loaded > config file path printed into console: > # perf daemon > Daemon process started with config /path/to/.perfconfig.daemon so the current way is, that following creates daemon: # perf daemon --config and any other 'non --config' option' is used to 'query/control' daemon: # perf daemon # perf daemon --signal # perf daemon --stop ... I'd like to keep short way checking on daemon, without too many options, like: # perf daemon [690174:daemon] base: /opt/perfdata [690175:top] perf record -e cycles --switch-output=1m --switch-max-files=6 -a I think maybe we don't need any other .perfconfig, we could have all in standard .perfconfig, like: # cat .perfconfig: [daemon] base=/opt/perfdata [session-1] run = -m 1M -e cycles --overwrite --switch-output -a [session-2] run = -m 1M -e sched:* --overwrite --switch-output -a and to run daemon on top of it: # perf daemon --start to run daemon with alternate config: # perf daemon --start= or: # perf daemon --start --config= and checking on daemon with default .perfconfig setup: # perf daemon checking on daemon with different base or config: # perf daemon --base= # perf daemon --config= # perf daemon --base= --stop # perf daemon --base= --signal # perf daemon --config= --stop # perf daemon --config= --signal how about that? SNIP > > +static struct session* > > +daemon__find_session(struct daemon *daemon, char *name) > > +{ > > + struct session *session; > > + > > + list_for_each_entry(session, &daemon->sessions, list) { > > + if (!strcmp(session->name, name)) > > + return session; > > + } > > + > > + return NULL; > > +} > > + > > +static int session_name(const char *var, char *session, int len) > > should possibly name it get_session_name. ok > > > +{ > > + const char *p = var + sizeof("session-") - 1; > > should possibly check that p still points inside [var, var+len). ok SNIP > > +static int session__wait(struct session *session, struct daemon *daemon, > > + int secs) > > +{ > > + time_t current, start = 0; > > + int cnt; > > + > > + start = current = time(NULL); > > + > > + do { > > + usleep(500); > > This polling design is actually sub-optimal because it induces redundant > noise in a system. Ideally it should be implemented in async fashion so > kernel would atomically notify daemon process on event happened in some > of record processes e.g. using of poll-like() system call. ok, any suggestion? > > > + cnt = session__check(session, daemon); > > + if (cnt) > > + break; > > + > > + current = time(NULL); > > + } while ((start + secs > current)); > > + > > + return cnt; > > +} > > + > > +static int session__signal(struct session *session, int sig) > > +{ > > + if (session->pid < 0) > > + return -1; > > + return kill(session->pid, sig); > > "Better" alternative could possibly be sending of some 'stop' command > via --control=fd. true, nice idea.. seems more clean and we already have control fd open will add it to next version thanks, jirka