From: Leo Yan <leo.yan@linaro.org> To: Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, 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>, Paul Cercueil <paul@crapouillou.net>, "Ben Dooks (Codethink)" <ben.dooks@codethink.co.uk>, "Ahmed S. Darwish" <a.darwish@linutronix.de>, Adrian Hunter <adrian.hunter@intel.com>, Kan Liang <kan.liang@linux.intel.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 3/6] arm64: perf: Only advertise cap_user_time for arch_timer Date: Wed, 15 Jul 2020 10:05:09 +0800 Message-ID: <20200715020512.20991-4-leo.yan@linaro.org> (raw) In-Reply-To: <20200715020512.20991-1-leo.yan@linaro.org> From: Peter Zijlstra <peterz@infradead.org> When sched_clock is running on anything other than arch_timer, don't advertise cap_user_time*. Requested-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/arm64/kernel/perf_event.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 35c2c737d4af..76f6afd28b48 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -13,6 +13,8 @@ #include <asm/sysreg.h> #include <asm/virt.h> +#include <clocksource/arm_arch_timer.h> + #include <linux/acpi.h> #include <linux/clocksource.h> #include <linux/kvm_host.h> @@ -1170,16 +1172,15 @@ void arch_perf_update_userpage(struct perf_event *event, unsigned int seq; u64 quot, rem, ns; - /* - * Internal timekeeping for enabled/running/stopped times - * is always computed with the sched_clock. - */ - userpg->cap_user_time = 1; - userpg->cap_user_time_zero = 1; + userpg->cap_user_time = 0; + userpg->cap_user_time_zero = 0; do { rd = sched_clock_read_begin(&seq); + if (rd->read_sched_clock != arch_timer_read_counter) + return; + userpg->time_mult = rd->mult; userpg->time_shift = rd->shift; userpg->time_zero = rd->epoch_ns; @@ -1211,4 +1212,10 @@ void arch_perf_update_userpage(struct perf_event *event, userpg->time_mult >>= 1; } + /* + * Internal timekeeping for enabled/running/stopped times + * is always computed with the sched_clock. + */ + userpg->cap_user_time = 1; + userpg->cap_user_time_zero = 1; } -- 2.17.1
next prev parent reply index Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-15 2:05 [PATCH v2 0/6] arm64: perf: Proper cap_user_time* support Leo Yan 2020-07-15 2:05 ` [PATCH v2 1/6] sched_clock: Expose struct clock_read_data Leo Yan 2020-07-15 5:56 ` Ahmed S. Darwish 2020-07-15 6:54 ` Leo Yan 2020-07-15 7:21 ` Ahmed S. Darwish 2020-07-15 8:12 ` Peter Zijlstra 2020-07-15 8:14 ` peterz 2020-07-15 9:23 ` Ahmed S. Darwish 2020-07-15 9:52 ` Peter Zijlstra 2020-07-15 11:59 ` [PATCH] time/sched_clock: Use raw_read_seqcount_latch() Ahmed S. Darwish 2020-07-15 15:29 ` Leo Yan 2020-07-15 15:58 ` Peter Zijlstra 2020-07-16 5:22 ` Leo Yan 2020-09-10 15:08 ` [tip: locking/core] time/sched_clock: Use raw_read_seqcount_latch() during suspend tip-bot2 for Ahmed S. Darwish 2020-07-15 2:05 ` [PATCH v2 2/6] arm64: perf: Implement correct cap_user_time Leo Yan 2020-07-15 8:38 ` Peter Zijlstra 2020-07-15 15:39 ` Leo Yan 2020-07-15 2:05 ` Leo Yan [this message] 2020-07-15 2:05 ` [PATCH v2 4/6] perf: Add perf_event_mmap_page::cap_user_time_short ABI Leo Yan 2020-07-15 2:05 ` [PATCH v2 5/6] arm64: perf: Add cap_user_time_short Leo Yan 2020-07-15 2:05 ` [PATCH v2 6/6] tools headers UAPI: Update tools's copy of linux/perf_event.h Leo Yan 2020-07-15 5:17 ` [PATCH v2 0/6] arm64: perf: Proper cap_user_time* support Ahmed S. Darwish 2020-07-15 6:29 ` Leo Yan
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