Received-SPF: pass (google.com: domain of linux-kernel+bounces-24387-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Message-ID: <9ce7c466-ce9d-4673-b89a-d3244226dbde@redhat.com>
Date: Fri, 12 Jan 2024 08:39:19 +0100
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v5] sched/stats: Fix rt/dl task's sched latency statistics
 error in sched_stat_wait tracepoint
To: Junwen Wu <wudaemon@163.com>, mingo@redhat.com, peterz@infradead.org,
 juri.lelli@redhat.com
Cc: mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org,
 laoar.shao@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
 rostedt@goodmis.org, bsegall@google.com
References: <20240111150147.182937-1-wudaemon@163.com>
Content-Language: en-US, pt-BR, it-IT
From: Daniel Bristot de Oliveira <bristot@redhat.com>
In-Reply-To: <20240111150147.182937-1-wudaemon@163.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit

On 1/11/24 16:01, Junwen Wu wrote:
> The sched_stat_wait tracepoint is showing unreasonably long
> latencies for real-time tasks. For example:
> 
> sched_stat_wait: comm=rcu_preempt pid=14 delay=4936139545261 [ns]
> 
> This error happens when the rt task balances off the source CPU because
> the dequeue operation is not updating the sched_statistics. So, follow
> update_stats_wait_end_fair() and update the stats. Do the same for
> SCHED_DEADLINE.
> 
> Fixes: 57a5c2dafca8 ("sched/rt: Support schedstats for RT sched class")
> Fixes: b5eb4a5f6521 ("sched/dl: Support schedstats for deadline sched class")

Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>

Thanks
-- Daniel