From: "Alex Bennée" <alex.bennee@linaro.org>
To: Pranith Kumar <bobby.prani@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Counting barrier instructions in ARM
Date: Fri, 17 Oct 2014 11:43:04 +0100 [thread overview]
Message-ID: <87tx337zbu.fsf@linaro.org> (raw)
In-Reply-To: <CAJhHMCBFQXzDhg8Ua7pM4uxtpGgydJsN-vy6cK3z2s6S0U=VyQ@mail.gmail.com>
Pranith Kumar <bobby.prani@gmail.com> writes:
> Hi Peter,
>
> On Thu, Oct 16, 2014 at 4:05 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 16 October 2014 03:45, Pranith Kumar <bobby.prani@gmail.com> wrote:
>>> The problem I am facing is that this seems to be crashing when run with a
>>> multi-threaded executable.
>>
>> This is nothing to do with your changes -- user-mode QEMU does not
>> support multi-threaded guest executables. QEMU may crash, hang,
>> or stop with an assertion failure, fairly randomly. Don't try
>> to run multithreaded guests :-)
>
> OK, I will try to gather the statistics in system mode. Is there any
> way to indicate from within the system to qemu to start collecting the stats?
>
> I dont want to collect the stats for bootup and other unrelated code
> paths.
You could enable CONTEXTIDR in the kernel and then make your counts
against an array indexed by it. I've used that technique before to
profile guest hot-blocks and work out which guest PID was responsible.
--
Alex Bennée
prev parent reply other threads:[~2014-10-17 10:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-16 1:45 [Qemu-devel] Counting barrier instructions in ARM Pranith Kumar
2014-10-16 1:54 ` Max Filippov
2014-10-16 2:00 ` Pranith Kumar
2014-10-16 2:12 ` Max Filippov
2014-10-16 16:05 ` Pranith Kumar
2014-10-16 8:05 ` Peter Maydell
2014-10-16 16:01 ` Pranith Kumar
2014-10-17 10:43 ` Alex Bennée [this message]
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