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.
prev parent 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 [PATCH PREEMPT_RT] kcov: fix locking splat from kcov_remote_start() 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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