On 7/8/20 7:38 AM, Sachin Sant wrote:
quoted
On 26-Jun-2020, at 10:17 PM, Desnes A. Nunes do Rosario [off-list ref] wrote:
An extra count on ebb_state.stats.pmc_count[PMC_INDEX(pmc)] is being per-
formed when count_pmc() is used to reset PMCs on a few selftests. This
extra pmc_count can occasionally invalidate results, such as the ones from
cycles_test shown hereafter. The ebb_check_count() failed with an above
the upper limit error due to the extra value on ebb_state.stats.pmc_count.
Furthermore, this extra count is also indicated by extra PMC1 trace_log on
the output of the cycle test (as well as on pmc56_overflow_test):
==========
...
[21]: counter = 8
[22]: register SPRN_MMCR0 = 0x0000000080000080
[23]: register SPRN_PMC1 = 0x0000000080000004
[24]: counter = 9
[25]: register SPRN_MMCR0 = 0x0000000080000080
[26]: register SPRN_PMC1 = 0x0000000080000004
[27]: counter = 10
[28]: register SPRN_MMCR0 = 0x0000000080000080
[29]: register SPRN_PMC1 = 0x0000000080000004
quoted
quoted
[30]: register SPRN_PMC1 = 0x000000004000051e
PMC1 count (0x280000546) above upper limit 0x2800003e8 (+0x15e)
[FAIL] Test FAILED on line 52
failure: cycles
==========
Signed-off-by: Desnes A. Nunes do Rosario <redacted>
---
I too have run into similar failure with cycles_test. I will add that the failure
is inconsistent. I have run into this issue 1 out of 25 times. The failure always
happen at first instance. Subsequent tries work correctly.
Indeed; on my tests I was running 100 times to validate.
Thanks for the review Sachin
With this patch applied the test completes successfully 25 out of 25 times.
# ./cycles_test
test: cycles
…..
…..
[25]: register SPRN_MMCR0 = 0x0000000080000080
[26]: register SPRN_PMC1 = 0x0000000080000004
[27]: counter = 10
[28]: register SPRN_MMCR0 = 0x0000000080000080
[29]: register SPRN_PMC1 = 0x0000000080000004
[30]: register SPRN_PMC1 = 0x000000004000048f
PMC1 count (0x2800004b7) above upper limit 0x2800003e8 (+0xcf)
[FAIL] Test FAILED on line 52
failure: cycles
With the patch
# ./cycles_test
test: cycles
…..
…..
[25]: register SPRN_MMCR0 = 0x0000000080000080
[26]: register SPRN_PMC1 = 0x0000000080000004
[27]: counter = 10
[28]: register SPRN_MMCR0 = 0x0000000080000080
[29]: register SPRN_PMC1 = 0x0000000080000004
PMC1 count (0x280000028) is between 0x27ffffc18 and 0x2800003e8 delta +0x410/-0x3c0
success: cycles
#
FWIW Tested-by : Sachin Sant [off-list ref]
Thanks
-Sachin
--
Desnes A. Nunes do Rosario
--------------------------------
Advisory Software Engineer - IBM
Virtual Onsite Engineer - Red Hat