From mboxrd@z Thu Jan  1 00:00:00 1970
From: compudj@krystal.dyndns.org (Mathieu Desnoyers)
Date: Fri, 26 Nov 2010 08:32:57 -0500
Subject: [ltt-dev] Kernel and User Space tracers have
	different	timestamp reference
In-Reply-To: <4CEFB138.6030409@polymtl.ca>
References: <20101126082453.4252.72312.launchpad@wampee.canonical.com>
	<4CEFB138.6030409@polymtl.ca>
Message-ID: <20101126133256.GA22133@Krystal>

Hi!

Yesterday evening, Julien and I were actively finishing the vDSO work
that is needed to have synchronized timestamps between the kernel LTTng
and UST on x86. It should be ready very soon. Keep posted for a new
release. :)

By the way, in the initial implementation, only 64-bit processes on
64-bit x86 systems with synchronized TSCs will benefit from the vDSO
speed. All other x86 setups will fallback on a system call, which will
still work, albeit being a bit slower.

Thanks,

Mathieu

* Alexandre Montplaisir (alexandre.montplaisir at polymtl.ca) wrote:
> Hi folks,
>
> I've received this bug report about kernel/UST trace synchronization.  
> Anyone knows what's the status on this?
>
> Thanks,
> Alexandre
>
>
> On 10-11-26 03:24 AM, Florent Boudet wrote:
>> Hello,
>>
>> I am sorry to contact you directly instead of filling a bug, but it
>> seems the option is disabled on the launchpad project...
>>
>> I have recorded userspace traces at the same time as kernel traces, and
>> opened both with LTTv.
>> Timestamp for userspace traces and timestamp for kernel traces have
>> different origins, which make it difficult to analyze.
>> I am not sure about the cause, this might be related to a GMT/localtime
>> issue...
>>
>> Regards,
>> Florent Boudet
>
>
> _______________________________________________
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> ltt-dev at lists.casi.polymtl.ca
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>

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com