From: Yao Qi <qiyaoltc@gmail.com>
To: Pedro Alves <palves@redhat.com>
Cc: Ulrich Weigand <uweigand@de.ibm.com>,
Yao Qi <qiyaoltc@gmail.com>,
Pierre Langlois <pierre.langlois@arm.com>,
gdb-patches@sourceware.org, cole945@gmail.com
Subject: Re: [PATCH 1/2] [GDBserver] Fix compiling conditional expressions accessing registers
Date: Wed, 16 Sep 2015 15:03:00 -0000 [thread overview]
Message-ID: <86pp1i1k5l.fsf@gmail.com> (raw)
In-Reply-To: <55F97479.9070807@redhat.com> (Pedro Alves's message of "Wed, 16 Sep 2015 14:54:01 +0100")
Pedro Alves <palves@redhat.com> writes:
>> Not sure whether this is a real performance concern for actual use
>> cases though. I don't have any actual measurements ...
>
> Yes, I was just now reading this, and was going to say the same.
>
> E.g., the original fast tracepoints code was tuned to avoid as much
> work as possible in the condition-fails scenario, when the condition
> only accesses a global. That is, e.g., "trace foo if debug_knob == 1".
> I no longer have the numbers captured at the time though.
I run tspeed.exp, and it shows this patch slows down fast tracepoint
from 29ns to 144ns, so we need to commit Wei-chang's patch
<https://sourceware.org/ml/gdb-patches/2015-06/msg00587.html> instead.
--
Yao (齐尧)
next prev parent reply other threads:[~2015-09-16 15:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-11 17:25 [PATCH 0/2] " Pierre Langlois
2015-09-11 17:25 ` [PATCH 1/2] " Pierre Langlois
2015-09-16 9:15 ` Yao Qi
2015-09-16 11:50 ` Ulrich Weigand
2015-09-16 13:54 ` Pedro Alves
2015-09-16 15:03 ` Yao Qi [this message]
2015-09-11 17:25 ` [PATCH 2/2] [testsuite] Add test case for tracepoints with conditions Pierre Langlois
2015-09-16 9:19 ` Yao Qi
2015-09-17 8:51 ` Yao Qi
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