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From: Ingo Molnar <mingo@elte.hu>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-mm <linux-mm@kvack.org>, Andi Kleen <andi@firstfloor.org>,
	Christoph Hellwig <hch@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Roland McGrath <roland@hack.frob.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Anton Arapov <anton@redhat.com>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Jim Keniston <jkenisto@linux.vnet.ibm.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [PATCH v9 3.2 7/9] tracing: uprobes trace_event interface
Date: Tue, 17 Jan 2012 13:21:33 +0100	[thread overview]
Message-ID: <20120117122133.GB4959@elte.hu> (raw)
In-Reply-To: <20120117102231.GB15447@linux.vnet.ibm.com>


Have you tried to use 'perf probe' to achieve any useful 
instrumentation on a real app?

I just tried out the 'glibc:free' usecase and it's barely 
usable.

Firstly, the recording very frequently produces overruns:

 $ perf record -e probe_libc:free -aR sleep 1
 [ perf record: Woken up 169 times to write data ]
 [ perf record: Captured and wrote 89.674 MB perf.data (~3917919 samples) ]
 Warning:Processed 1349133 events and lost 1 chunks!

Using -m 4096 made it work better.

Adding -g for call-graph profiling caused 'perf report' to lock 
up:

  perf record -m 4096 -e probe_libc:free -agR sleep 1
  perf report
  [ loops forever ]

I've sent a testcase to Arnaldo separately. Note that perf 
report --stdio appears to work.

Regular '-e cycles -g' works fine, so this is a uprobes specific 
bug.

Thanks,

	Ingo

  parent reply	other threads:[~2012-01-17 12:22 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-10 11:48 [PATCH v9 3.2 0/9] Uprobes patchset with perf probe support Srikar Dronamraju
2012-01-10 11:48 ` [PATCH v9 3.2 1/9] uprobes: Install and remove breakpoints Srikar Dronamraju
2012-01-25 14:39   ` Denys Vlasenko
2012-01-25 16:31     ` Oleg Nesterov
2012-01-25 15:13   ` Denys Vlasenko
2012-01-25 15:32     ` Denys Vlasenko
2012-01-26 14:14       ` Masami Hiramatsu
2012-01-26 18:28         ` Denys Vlasenko
2012-01-30  9:51           ` Masami Hiramatsu
2012-01-26 13:38     ` Masami Hiramatsu
2012-01-26 13:45   ` Masami Hiramatsu
2012-01-10 11:48 ` [PATCH v9 3.2 2/9] uprobes: handle breakpoint and signal step exception Srikar Dronamraju
2012-01-18  8:39   ` Anton Arapov
2012-01-18  9:02     ` Srikar Dronamraju
2012-01-18 10:18       ` Mike Frysinger
2012-01-18 10:47         ` Srikar Dronamraju
2012-01-18 11:01           ` Mike Frysinger
2012-01-20 22:57             ` Mike Frysinger
2012-01-25  8:12               ` Srikar Dronamraju
2012-01-10 11:48 ` [PATCH v9 3.2 3/9] uprobes: slot allocation Srikar Dronamraju
2012-01-10 11:49 ` [PATCH v9 3.2 4/9] uprobes: counter to optimize probe hits Srikar Dronamraju
2012-01-10 11:49 ` [PATCH v9 3.2 5/9] tracing: modify is_delete, is_return from ints to bool Srikar Dronamraju
2012-01-10 11:49 ` [PATCH v9 3.2 6/9] tracing: Extract out common code for kprobes/uprobes traceevents Srikar Dronamraju
2012-01-10 11:49 ` [PATCH v9 3.2 7/9] tracing: uprobes trace_event interface Srikar Dronamraju
2012-01-16 13:11   ` Jiri Olsa
2012-01-16 14:45     ` Srikar Dronamraju
2012-01-16 15:33       ` Jiri Olsa
2012-01-16 16:41         ` Srikar Dronamraju
2012-01-17  9:28     ` Ingo Molnar
2012-01-17 10:22       ` Srikar Dronamraju
2012-01-17 10:59         ` Ingo Molnar
2012-01-17 11:03           ` Srikar Dronamraju
2012-01-17 11:22         ` Ingo Molnar
2012-01-17 11:57           ` Srikar Dronamraju
2012-01-17 12:23             ` Ingo Molnar
2012-01-17 12:27               ` Ingo Molnar
2012-01-17 12:11         ` Ingo Molnar
2012-01-17 12:21         ` Ingo Molnar [this message]
2012-01-18 10:07           ` Srikar Dronamraju
2012-01-10 11:49 ` [PATCH v9 3.2 8/9] perf: rename target_module to target Srikar Dronamraju
2012-01-16  8:34 ` [PATCH v9 3.2 0/9] Uprobes patchset with perf probe support Ingo Molnar
2012-01-16 15:17   ` Srikar Dronamraju
2012-01-17  9:39     ` Ingo Molnar
2012-01-25 14:11       ` Peter Zijlstra
2012-01-26 11:10         ` Ingo Molnar

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