RE: [PATCH 1/1] Reduce synchronize_rcu() waiting time

From: "Zhuo, Qiuxu" <qiuxu.zhuo@intel.com>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
	RCU <rcu@vger.kernel.org>,
	"quic_neeraju@quicinc.com" <quic_neeraju@quicinc.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Frederic Weisbecker <frederic@kernel.org>
Subject: RE: [PATCH 1/1] Reduce synchronize_rcu() waiting time
Date: Wed, 22 Mar 2023 01:49:50 +0000	[thread overview]
Message-ID: <SJ1PR11MB61795652651F41A8F94B1E9D89869@SJ1PR11MB6179.namprd11.prod.outlook.com> (raw)
In-Reply-To: <ZBnKKZsSpI8aAk9W@pc636>

Hi Rezki,

> From: Uladzislau Rezki <urezki@gmail.com>
> Sent: Tuesday, March 21, 2023 11:16 PM
> [...]
> >
> >
> > If possible, may I know the steps, commands, and related parameters to
> produce the results above?
> > Thank you!
> >
> Build the kernel with CONFIG_RCU_TRACE configuration. Update your
> "set_event"
> file with appropriate traces:
> 
> <snip>
> XQ-DQ54:/sys/kernel/tracing # echo rcu:rcu_batch_start rcu:rcu_batch_end
> rcu:rcu_invoke_callback > set_event
> 
> XQ-DQ54:/sys/kernel/tracing # cat set_event rcu:rcu_batch_start
> rcu:rcu_invoke_callback rcu:rcu_batch_end XQ-DQ54:/sys/kernel/tracing #
> <snip>
> 
> Collect traces as much as you want: XQ-DQ54:/sys/kernel/tracing # echo 1 >
> tracing_on; sleep 10; echo 0 > tracing_on Next problem is how to parse it. Of

Thanks for the detailed steps to collect the related testing results.

> course you will not be able to parse megabytes of traces. For that purpose i
> use a special C trace parser.
> If you need an example please let me know i can show here.
>

Yes, your example parser should save me from a huge amount of traces. ;-)
Thanks so much for your sharing.

- Qiuxu

> --
> Uladzislau Rezki