Hard lockup with timer events
From: Soeren Sandmann
Date: Thu Oct 29 2009 - 15:15:14 EST
Hi,
This program
http://www.daimi.au.dk/~sandmann/lockup.c
locks up hard for me on a Pentium 4 in 32 bit mode, with the hrtimer
patches applied (-tip for example).
What the program does is spawn a thread that just spins, and then 400
threads that each create a performance counter of type
PERF_COUNT_SW_CPU_CLOCK and a sample period of 1000000 and a
sample_type of
PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_CALLCHAIN
These threads then map the event buffer and read it continuously.
It does not apparently lock up if SAMPLE_CALLCHAIN is removed; also I
cannot get it to lock up on Core 2 Duo in either 32 or 64 bit mode.
Soren
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