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Date: Thu, 25 Mar 2010 16:02:09 +0800
From: Li Zefan <lizf@cn.fujitsu.com>
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To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
CC: Ingo Molnar <mingo@elte.hu>, Arnaldo Carvalho de Melo <acme@redhat.com>,
       Avi Kivity <avi@redhat.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       linux-kernel@vger.kernel.org, Sheng Yang <sheng@linux.intel.com>,
       oerg Roedel <joro@8bytes.org>, Jes Sorensen <Jes.Sorensen@redhat.com>,
       Marcelo Tosatti <mtosatti@redhat.com>, Gleb Natapov <gleb@redhat.com>,
       kvm@vger.kernel.org, zhiteng.huang@intel.com,
       Zachary Amsden <zamsden@redhat.com>
Subject: Re: [PATCH 3/3] perf events: Change perf parameter --pid to process-wide
 collection instead of thread-wide
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Zhang, Yanmin wrote:
> From: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
> 
> Parameter --pid (or -p) of perf currently means a thread-wide collection.
> For exmaple, if a process whose id is 8888 has 10 threads, 'perf top -p 8888'
> just collects the main thread statistics. That's misleading. Users are
> used to attach a whole process when debugging a process by gdb. To follow
> normal usage style, the patch change --pid to process-wide collection and
> add --tid (-t) to mean a thread-wide collection.
> 
> Usage example is:
> #perf top -p 8888
> #perf record -p 8888 -f sleep 10
> #perf stat -p 8888 -f sleep 10
> Above commands collect the statistics of all threads of process 8888.
> 
> Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
> 

Seems this patch causes seg faults:

# ./perf sched record
Segmentation fault
# ./perf kmem record
Segmentation fault
# ./perf timechart record
Segmentation fault