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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AA3BC433F5 for ; Sat, 23 Oct 2021 02:23:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4151C6101C for ; Sat, 23 Oct 2021 02:23:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230086AbhJWCZX (ORCPT ); Fri, 22 Oct 2021 22:25:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:40742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbhJWCZX (ORCPT ); Fri, 22 Oct 2021 22:25:23 -0400 Received: from rorschach.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6D35960FF2; Sat, 23 Oct 2021 02:23:03 +0000 (UTC) Date: Fri, 22 Oct 2021 22:23:01 -0400 From: Steven Rostedt To: Daniel Bristot de Oliveira Cc: Ingo Molnar , Tom Zanussi , Masami Hiramatsu , Juri Lelli , Clark Williams , John Kacur , Peter Zijlstra , Thomas Gleixner , Sebastian Andrzej Siewior , linux-rt-users@vger.kernel.org, linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V4 01/19] trace/osnoise: Do not follow tracing_cpumask Message-ID: <20211022222301.32c2d869@rorschach.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Thu, 21 Oct 2021 14:56:39 +0200 Daniel Bristot de Oliveira wrote: > In preparation to support multiple instances, decople the "decouple" > osnoise/timelat workload from instance specific tracing_cpumask. > > Different instances can have conflicing cpumasks, making osnoise "conflicting" May I suggest a spell check for your commit logs? ;-) > workload management needlessly complex. Osnoise already have its > global cpu mask. > > I also thought about using the first instance mask, but the > "first" instance could be removed before the others. > > This also fixes the problem that changing the tracing_mask was not > re-starting the trace. > > Cc: Steven Rostedt > Cc: Ingo Molnar > Cc: Tom Zanussi > Cc: Masami Hiramatsu > Cc: Juri Lelli > Cc: Clark Williams > Cc: John Kacur > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Sebastian Andrzej Siewior > Cc: Daniel Bristot de Oliveira > Cc: linux-rt-users@vger.kernel.org > Cc: linux-trace-devel@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Daniel Bristot de Oliveira > --- > kernel/trace/trace_osnoise.c | 25 +++++++------------------ > 1 file changed, 7 insertions(+), 18 deletions(-) > > diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c > index ce053619f289..7b1f8187764c 100644 > --- a/kernel/trace/trace_osnoise.c > +++ b/kernel/trace/trace_osnoise.c > @@ -1553,13 +1553,10 @@ static int start_per_cpu_kthreads(struct trace_array *tr) > > cpus_read_lock(); > /* > - * Run only on CPUs in which trace and osnoise are allowed to run. > + * Run only on online CPUs in which trace and osnoise are allowed to which trace and osnise? I thought we were removing "trace"? -- Steve > + * run. > */ > - cpumask_and(current_mask, tr->tracing_cpumask, &osnoise_cpumask); > - /* > - * And the CPU is online. > - */ > - cpumask_and(current_mask, cpu_online_mask, current_mask); > + cpumask_and(current_mask, cpu_online_mask, &osnoise_cpumask); > > for_each_possible_cpu(cpu) > per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL; > @@ -1580,10 +1577,8 @@ static int start_per_cpu_kthreads(struct trace_array *tr) > #ifdef CONFIG_HOTPLUG_CPU > static void osnoise_hotplug_workfn(struct work_struct *dummy) > { > - struct trace_array *tr = osnoise_trace; > unsigned int cpu = smp_processor_id(); > > - > mutex_lock(&trace_types_lock); > > if (!osnoise_busy) > @@ -1595,9 +1590,6 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy) > if (!cpumask_test_cpu(cpu, &osnoise_cpumask)) > goto out_unlock; > > - if (!cpumask_test_cpu(cpu, tr->tracing_cpumask)) > - goto out_unlock; > - > start_kthread(cpu); > > out_unlock: > @@ -1700,13 +1692,10 @@ static void osnoise_tracer_stop(struct trace_array *tr); > * interface to the osnoise trace. By default, it lists all CPUs, > * in this way, allowing osnoise threads to run on any online CPU > * of the system. It serves to restrict the execution of osnoise to the > - * set of CPUs writing via this interface. Note that osnoise also > - * respects the "tracing_cpumask." Hence, osnoise threads will run only > - * on the set of CPUs allowed here AND on "tracing_cpumask." Why not > - * have just "tracing_cpumask?" Because the user might be interested > - * in tracing what is running on other CPUs. For instance, one might > - * run osnoise in one HT CPU while observing what is running on the > - * sibling HT CPU. > + * set of CPUs writing via this interface. Why not use "tracing_cpumask"? > + * Because the user might be interested in tracing what is running on > + * other CPUs. For instance, one might run osnoise in one HT CPU > + * while observing what is running on the sibling HT CPU. > */ > static ssize_t > osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,