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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-12-14 23:34:37 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-12-14 23:34:37 +0300 |
| commit | 81d559849aa4d972a2d297840eefdd20c4054131 (patch) | |
| tree | 8749eee120145a1ad526f5a9327827121883a5f4 /arch/s390/kernel/perf_cpum_sf.c | |
| parent | f791ede32a14151a313783e1105049a137bc13c8 (diff) | |
| parent | 3e39ce266a273e5751e5792aee248cb8d9630c8b (diff) | |
| download | linux-81d559849aa4d972a2d297840eefdd20c4054131.tar.xz | |
Merge tag 's390-5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Add support for KASAN_VMALLOC feature.
- Remove the last user of problematic diag 0x44 call.
- Adjust sampling interval and avoid sample data block overflow
condition on pressure in perf code.
- Prefer EOPNOTSUPP over ENOTSUPP and comments fixes.
* tag 's390-5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/kasan: add KASAN_VMALLOC support
s390: remove last diag 0x44 caller
s390/uv: use EOPNOTSUPP instead of ENOTSUPP
s390/cpum_sf: Avoid SBD overflow condition in irq handler
s390/cpum_sf: Adjust sampling interval to avoid hitting sample limits
s390/test_unwind: fix spelling mistake "reqister" -> "register"
s390/spinlock: remove confusing comment in arch_spin_lock_wait
Diffstat (limited to 'arch/s390/kernel/perf_cpum_sf.c')
| -rw-r--r-- | arch/s390/kernel/perf_cpum_sf.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index c07fdcd73726..77d93c534284 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -1303,18 +1303,28 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all) */ if (flush_all && done) break; - - /* If an event overflow happened, discard samples by - * processing any remaining sample-data-blocks. - */ - if (event_overflow) - flush_all = 1; } /* Account sample overflows in the event hardware structure */ if (sampl_overflow) OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + sampl_overflow, 1 + num_sdb); + + /* Perf_event_overflow() and perf_event_account_interrupt() limit + * the interrupt rate to an upper limit. Roughly 1000 samples per + * task tick. + * Hitting this limit results in a large number + * of throttled REF_REPORT_THROTTLE entries and the samples + * are dropped. + * Slightly increase the interval to avoid hitting this limit. + */ + if (event_overflow) { + SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); + debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", + __func__, + DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); + } + if (sampl_overflow || event_overflow) debug_sprintf_event(sfdbg, 4, "%s: " "overflows: sample %llu event %llu" |