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author | Matt Evans | 2010-07-05 17:36:32 +0000 |
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committer | Benjamin Herrenschmidt | 2010-07-08 18:11:37 +1000 |
commit | 219a92a4c40db2fac604f63bce9a5a3fe1967879 (patch) | |
tree | a02b36dca8a413ca6793b316afbd7e5592d7ae7b /arch/powerpc/kernel/prom_init_check.sh | |
parent | 2aa72f612144a0a7d4b0b22ae7c122692ac6a013 (diff) |
powerpc/perf_event: Fix for power_pmu_disable()
When power_pmu_disable() removes the given event from a particular index into
cpuhw->event[], it shuffles down higher event[] entries. But, this array is
paired with cpuhw->events[] and cpuhw->flags[] so should shuffle them
similarly.
If these arrays get out of sync, code such as power_check_constraints() will
fail. This caused a bug where events were temporarily disabled and then failed
to be re-enabled; subsequent code tried to write_pmc() with its (disabled) idx
of 0, causing a message "oops trying to write PMC0". This triggers this bug on
POWER7, running a miss-heavy test:
perf record -e L1-dcache-load-misses -e L1-dcache-store-misses ./misstest
Signed-off-by: Matt Evans <matt@ozlabs.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/prom_init_check.sh')
0 files changed, 0 insertions, 0 deletions