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From: Thomas Gleixner <tglx@linutronix.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Clark Williams <williams@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH PREEMPT_RT] kcov:  fix locking splat from kcov_remote_start()
Date: Wed, 11 Aug 2021 14:25:29 +0200	[thread overview]
Message-ID: <87czqkp3ra.ffs@tglx> (raw)
In-Reply-To: <20210811090033.wijh4v37wlnny3ox@linutronix.de>

On Wed, Aug 11 2021 at 11:00, Sebastian Andrzej Siewior wrote:
> On 2021-08-10 22:38:30 [+0200], Thomas Gleixner wrote:
>> And that matters because? kcov has a massive overhead and with that
>> enabled you care as much about latencies as you do when running with
>> lockdep enabled.
>
> I wasn't aware of that. However, with that local_irq_save() ->
> local_lock_irqsave() swap and that first C code from
> Documentation/dev-tools/kcov.rst I don't see any spike in cyclictest's
> results. Maybe I'm not using it right…

The problem starts with remote coverage AFAICT.

      reply	other threads:[~2021-08-11 12:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-09 20:59 Clark Williams
2021-08-10  9:42 ` Marco Elver
2021-08-10  9:50 ` Sebastian Andrzej Siewior
2021-08-10 19:14   ` Steven Rostedt
2021-08-10 20:38   ` Thomas Gleixner
2021-08-11  9:00     ` Sebastian Andrzej Siewior
2021-08-11 12:25       ` Thomas Gleixner [this message]

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