From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Leo Yan <leo.yan@linaro.org>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, mingo@redhat.com,
acme@kernel.org, alexander.shishkin@linux.intel.com,
jolsa@redhat.com, daniel.lezcano@linaro.org, tglx@linutronix.de,
sboyd@codeaurora.org, john.stultz@linaro.org,
"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [PATCH 3/5] arm64: perf: Only advertise cap_user_time for arch_timer
Date: Tue, 12 May 2020 14:41:01 +0200 [thread overview]
Message-ID: <20200512124450.903534446@infradead.org> (raw)
In-Reply-To: 20200512124058.833263033@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(-)
--- 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>
@@ -1169,16 +1171,15 @@ void arch_perf_update_userpage(struct pe
struct clock_read_data *rd;
unsigned int seq;
- /*
- * 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;
@@ -1207,4 +1208,10 @@ void arch_perf_update_userpage(struct pe
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;
}
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Leo Yan <leo.yan@linaro.org>
Cc: alexander.shishkin@linux.intel.com, daniel.lezcano@linaro.org,
sboyd@codeaurora.org, linux-kernel@vger.kernel.org,
acme@kernel.org,
"Peter Zijlstra \(Intel\)" <peterz@infradead.org>,
mingo@redhat.com, john.stultz@linaro.org, tglx@linutronix.de,
jolsa@redhat.com, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/5] arm64: perf: Only advertise cap_user_time for arch_timer
Date: Tue, 12 May 2020 14:41:01 +0200 [thread overview]
Message-ID: <20200512124450.903534446@infradead.org> (raw)
In-Reply-To: 20200512124058.833263033@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(-)
--- 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>
@@ -1169,16 +1171,15 @@ void arch_perf_update_userpage(struct pe
struct clock_read_data *rd;
unsigned int seq;
- /*
- * 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;
@@ -1207,4 +1208,10 @@ void arch_perf_update_userpage(struct pe
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;
}
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next prev parent reply other threads:[~2020-05-12 12:47 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 12:40 [PATCH 0/5] arm64: perf: Proper cap_user_time* support Peter Zijlstra
2020-05-12 12:40 ` Peter Zijlstra
2020-05-12 12:40 ` [PATCH 1/5] sched_clock: Expose struct clock_read_data Peter Zijlstra
2020-05-12 12:40 ` Peter Zijlstra
2020-05-12 12:41 ` [PATCH 2/5] arm64: perf: Implement correct cap_user_time Peter Zijlstra
2020-05-12 12:41 ` Peter Zijlstra
2020-05-12 14:03 ` Leo Yan
2020-05-12 14:03 ` Leo Yan
2020-05-12 14:08 ` Peter Zijlstra
2020-05-12 14:08 ` Peter Zijlstra
2020-05-12 16:05 ` kbuild test robot
2020-05-12 16:05 ` kbuild test robot
2020-05-12 16:05 ` kbuild test robot
2020-05-12 12:41 ` Peter Zijlstra [this message]
2020-05-12 12:41 ` [PATCH 3/5] arm64: perf: Only advertise cap_user_time for arch_timer Peter Zijlstra
2020-05-12 12:41 ` [PATCH 4/5] perf: Add perf_event_mmap_page::cap_user_time_short ABI Peter Zijlstra
2020-05-12 12:41 ` Peter Zijlstra
2020-05-12 12:41 ` [PATCH 5/5] arm64: perf: Add cap_user_time_short Peter Zijlstra
2020-05-12 12:41 ` Peter Zijlstra
2020-05-12 14:11 ` Leo Yan
2020-05-12 14:11 ` Leo Yan
2020-05-12 16:59 ` kbuild test robot
2020-05-12 16:59 ` kbuild test robot
2020-05-12 16:59 ` kbuild test robot
2020-07-13 6:08 ` [PATCH 0/5] arm64: perf: Proper cap_user_time* support Leo Yan
2020-07-13 6:08 ` Leo Yan
2020-07-13 10:11 ` Will Deacon
2020-07-13 10:11 ` Will Deacon
2020-07-13 12:58 ` Leo Yan
2020-07-13 12:58 ` Leo Yan
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