From: Leo Yan <leo.yan@linaro.org>
To: Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
"Ben Dooks (Codethink)" <ben.dooks@codethink.co.uk>,
Paul Cercueil <paul@crapouillou.net>,
Adrian Hunter <adrian.hunter@intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v3 6/7] arm64: perf: Add cap_user_time_short
Date: Thu, 16 Jul 2020 13:11:29 +0800 [thread overview]
Message-ID: <20200716051130.4359-7-leo.yan@linaro.org> (raw)
In-Reply-To: <20200716051130.4359-1-leo.yan@linaro.org>
From: Peter Zijlstra <peterz@infradead.org>
This completes the ARM64 cap_user_time support.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
arch/arm64/kernel/perf_event.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index c016b116ae33..888bcb5d1388 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1174,6 +1174,7 @@ void arch_perf_update_userpage(struct perf_event *event,
userpg->cap_user_time = 0;
userpg->cap_user_time_zero = 0;
+ userpg->cap_user_time_short = 0;
do {
rd = sched_clock_read_begin(&seq);
@@ -1184,13 +1185,13 @@ void arch_perf_update_userpage(struct perf_event *event,
userpg->time_mult = rd->mult;
userpg->time_shift = rd->shift;
userpg->time_zero = rd->epoch_ns;
+ userpg->time_cycles = rd->epoch_cyc;
+ userpg->time_mask = rd->sched_clock_mask;
/*
- * This isn't strictly correct, the ARM64 counter can be
- * 'short' and then we get funnies when it wraps. The correct
- * thing would be to extend the perf ABI with a cycle and mask
- * value, but because wrapping on ARM64 is very rare in
- * practise this 'works'.
+ * Subtract the cycle base, such that software that
+ * doesn't know about cap_user_time_short still 'works'
+ * assuming no wraps.
*/
ns = mul_u64_u32_shr(rd->epoch_cyc, rd->mult, rd->shift);
userpg->time_zero -= ns;
@@ -1216,4 +1217,5 @@ void arch_perf_update_userpage(struct perf_event *event,
*/
userpg->cap_user_time = 1;
userpg->cap_user_time_zero = 1;
+ userpg->cap_user_time_short = 1;
}
--
2.17.1
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next prev parent reply other threads:[~2020-07-16 5:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 5:11 [PATCH v3 0/7] arm64: perf: Proper cap_user_time* support Leo Yan
2020-07-16 5:11 ` [PATCH v3 1/7] sched_clock: Expose struct clock_read_data Leo Yan
2020-07-16 5:11 ` [PATCH v3 2/7] time/sched_clock: Use raw_read_seqcount_latch() Leo Yan
2020-07-16 5:11 ` [PATCH v3 3/7] arm64: perf: Implement correct cap_user_time Leo Yan
2020-07-16 5:11 ` [PATCH v3 4/7] arm64: perf: Only advertise cap_user_time for arch_timer Leo Yan
2020-07-16 5:11 ` [PATCH v3 5/7] perf: Add perf_event_mmap_page::cap_user_time_short ABI Leo Yan
2020-07-16 5:11 ` Leo Yan [this message]
2020-07-16 5:11 ` [PATCH v3 7/7] tools headers UAPI: Update tools's copy of linux/perf_event.h Leo Yan
2020-07-20 11:56 ` [PATCH v3 0/7] arm64: perf: Proper cap_user_time* support Will Deacon
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