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From: "Lluís Vilanova" <vilanova@ac.upc.edu>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: qemu-devel@nongnu.org, den@openvz.org, dgilbert@redhat.com,
	stefanha@redhat.com, armbru@redhat.com
Subject: Re: [Qemu-devel] [PATCH 0/2] improve tracing
Date: Fri, 21 Jul 2017 20:04:17 +0300	[thread overview]
Message-ID: <87a83xlo1a.fsf@frigg.lan> (raw)
In-Reply-To: <20170721143149.43721-1-vsementsov@virtuozzo.com> (Vladimir Sementsov-Ogievskiy's message of "Fri, 21 Jul 2017 17:31:47 +0300")

Vladimir Sementsov-Ogievskiy writes:

> Current trace system have a drawback: parameters of trace functions
> are calculated even if corresponding tracepoint is disabled. Also, it
> looks like trace function are not actually inlined by compiler (at
> least for me).

> Here is a fix proposal: move from function call to macros. Patch 02
> is an example, of how to reduce extra calculations with help of
> patch 01.

The tracing functions *were* inlined last time I checked, although things
changed quite a lot since then. Not sure that will make a lot of difference in
terms of overall performance (needs measuring).

As for arguments, each trace event has a define TRACE_{NAME}_ENABLED that you
can use for that purpose. If this is not explained in tracing.txt, that is a
documentation bug.


Thanks,
  Lluis

  parent reply	other threads:[~2017-07-21 17:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-21 14:31 [Qemu-devel] [PATCH 0/2] improve tracing Vladimir Sementsov-Ogievskiy
2017-07-21 14:31 ` [Qemu-devel] [PATCH 1/2] trace: do not calculate arguments for disabled trace-points Vladimir Sementsov-Ogievskiy
2017-07-21 14:31 ` [Qemu-devel] [PATCH 2/2] monitor: improve tracing in handle_qmp_command Vladimir Sementsov-Ogievskiy
2017-07-24 11:39   ` Stefan Hajnoczi
2017-07-21 17:04 ` Lluís Vilanova [this message]
2017-07-24  8:55   ` [Qemu-devel] [PATCH 0/2] improve tracing Vladimir Sementsov-Ogievskiy
2017-07-24 11:07     ` Lluís Vilanova
2017-07-24 11:16       ` Denis V. Lunev
2017-07-24 11:32   ` Stefan Hajnoczi
2017-07-24 11:34 ` Stefan Hajnoczi
2017-07-24 12:17   ` Denis V. Lunev
2017-07-24 14:43     ` Lluís Vilanova
2017-07-24 14:55       ` Denis V. Lunev
2017-07-24 16:32         ` Lluís Vilanova
2017-07-25 13:52           ` Stefan Hajnoczi
2017-07-24 16:24     ` Philippe Mathieu-Daudé

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