s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur
authorHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Thu, 12 Dec 2013 16:03:48 +0000 (17:03 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 16 Dec 2013 13:37:57 +0000 (14:37 +0100)
commit69f239ed335a4b03265cae3ca930f3f166e42e35
tree3a3f8debcc51fa4f1e81f1f15446737bc4e04a41
parent257608fb4112b4cabefd9e33a4fc2df6b64dca6a
s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur

Improve the sampling buffer allocation and add a function to reallocate and
increase the sampling buffer structure.  The number of allocated buffer elements
(sample-data-blocks) are accounted.  You can control the minimum and maximum
number these sample-data-blocks through the cpum_sfb_size kernel parameter.

The number hardware sample overflows (if any) are also accounted and stored
per perf event.  During the PMU disable/enable calls, the accumulated overflow
counter is analyzed and, if necessary, the sampling buffer is dynamically
increased.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/include/asm/perf_event.h
arch/s390/kernel/perf_cpum_sf.c