From: Tom Tromey <tromey@redhat.com>
To: Pedro Alves <palves@redhat.com>
Cc: Sergio Durigan Junior <sergiodj@redhat.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH 2/3] Implement new features needed for handling SystemTap probes
Date: Thu, 15 Mar 2012 20:50:00 -0000 [thread overview]
Message-ID: <87ehsty4g2.fsf@fleche.redhat.com> (raw)
In-Reply-To: <4F620C71.8060501@redhat.com> (Pedro Alves's message of "Thu, 15 Mar 2012 15:36:17 +0000")
>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:
Pedro> I don't understand why we'd now skip the test when we don't have
Pedro> the unwinder stap probe,
I think the patch checks for the probe and for the unwinder debug hook,
and bails if they are both missing.
If either one exists then the test should work.
Pedro> This made me wonder about something else with this semaphore
Pedro> handling: the target can itself stop tracing, without GDB requesting
Pedro> it. E.g., if the trace buffer is full. If so, then you'll miss
Pedro> decrementing the semaphore count... Even worse with disconnected
Pedro> tracing; GDB might not even be connected when the tracing stops,
Pedro> and when you reconnect, you have no clue whether to decrement
Pedro> the counts or not...
Leaving the semaphore enabled in corner cases is not terrible.
It may affect performance a little, but that is all.
Anyone affected will already be doing reasonably sophisticated
debugging -- running disconnected trace experiments. If it is important
they could also just reset the semaphore to 0 manually.
Tom
next prev parent reply other threads:[~2012-03-15 20:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-09 20:29 [PATCH 0/3] Implement support for SystemTap probes on userspace Sergio Durigan Junior
2012-03-09 20:32 ` [PATCH 1/3] Refactor internal variable mechanism Sergio Durigan Junior
2012-03-09 21:03 ` Tom Tromey
2012-03-10 4:02 ` Sergio Durigan Junior
2012-03-09 20:34 ` [PATCH 2/3] Implement new features needed for handling SystemTap probes Sergio Durigan Junior
2012-03-10 8:38 ` Eli Zaretskii
2012-03-10 16:56 ` Mark Kettenis
2012-03-12 15:11 ` Tom Tromey
2012-03-13 8:58 ` Mark Kettenis
2012-03-13 16:06 ` Sergio Durigan Junior
2012-03-15 20:44 ` Tom Tromey
2012-03-16 14:52 ` Mark Kettenis
2012-03-16 18:17 ` Tom Tromey
2012-03-10 19:22 ` Jan Kratochvil
2012-03-12 20:37 ` Tom Tromey
2012-03-12 23:15 ` Jan Kratochvil
2012-03-15 15:40 ` Pedro Alves
2012-03-15 15:36 ` Pedro Alves
2012-03-15 20:50 ` Tom Tromey [this message]
2012-03-09 20:34 ` [PATCH 3/3] Use longjmp and exception probes when available Sergio Durigan Junior
2012-03-09 21:15 ` [PATCH 0/3] Implement support for SystemTap probes on userspace Tom Tromey
2012-03-10 3:51 ` Sergio Durigan Junior
2012-03-10 7:55 ` Eli Zaretskii
2012-03-10 8:55 ` Jan Kratochvil
2012-03-10 9:06 ` Eli Zaretskii
2012-03-10 15:52 ` Sergio Durigan Junior
2012-03-12 19:59 ` Tom Tromey
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