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From: Darren Hart <dvhltc@linux.vnet.ibm.com>
To: linux-rt-users@vger.kernel.org
Cc: "lkml, " <linux-kernel@vger.kernel.org>
Subject: Using CONFIG_FUNCTION_TRACE
Date: Thu, 13 Dec 2007 22:11:22 -0800	[thread overview]
Message-ID: <200712132211.23003.dvhltc@linux.vnet.ibm.com> (raw)

I was trying to use CONFIG_FUNCTION_TRACE with the example trace-it.c in 
linux/scripts.  On both 2.6.23.9-rt13 and 2.6.24-rc2-rt1 the system 
slower becomes less responsive (measured by typing in ssh and a serial 
console) until after a couple minutes it doesn't respond to anything 
including sysrq, requiring a power cycle.

The trace-it.c program defaults to 10 seconds of tracing, I even tried 
dropping that to 100 us in case it just added so much overhead that 10 
seconds of idle turned into minutes.  But the 100us sleep hung too.

I tested on a 4 way (2x2) opteron.  

I enabled:

CONFIG_EVENT_TRACE
CONFIG_FUNCTION_TRACE

Thanks,

-- 
Darren Hart
IBM Linux Technology Center
Real-Time Linux Team

                 reply	other threads:[~2007-12-14  6:11 UTC|newest]

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