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From: Stephen Boyd <sboyd@codeaurora.org>
To: Rob Herring <robherring2@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Russell King <linux@arm.linux.org.uk>,
	arm@kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	John Stultz <john.stultz@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 2/4] ARM: sched_clock: Return suspended count earlier
Date: Fri, 19 Apr 2013 17:29:04 -0700	[thread overview]
Message-ID: <1366417746-24990-3-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1366417746-24990-1-git-send-email-sboyd@codeaurora.org>

If we're suspended and sched_clock() is called we're going to
read the hardware one more time and throw away that value and
return back the cached value we saved during the suspend
callback. This is wasteful, let's short circuit all that and
return the cached value if we're suspended as early as possible.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/kernel/sched_clock.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
index 48ab64a..29ac613 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -55,9 +55,6 @@ static unsigned long long cyc_to_sched_clock(u32 cyc, u32 mask)
 	u64 epoch_ns;
 	u32 epoch_cyc;
 
-	if (cd.suspended)
-		return cd.epoch_ns;
-
 	/*
 	 * Load the epoch_cyc and epoch_ns atomically.  We do this by
 	 * ensuring that we always write epoch_cyc, epoch_ns and
@@ -174,6 +171,9 @@ unsigned long long __read_mostly (*sched_clock_func)(void) = sched_clock_32;
 
 unsigned long long notrace sched_clock(void)
 {
+	if (cd.suspended)
+		return cd.epoch_ns;
+
 	return sched_clock_func();
 }
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

WARNING: multiple messages have this Message-ID (diff)
From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/4] ARM: sched_clock: Return suspended count earlier
Date: Fri, 19 Apr 2013 17:29:04 -0700	[thread overview]
Message-ID: <1366417746-24990-3-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1366417746-24990-1-git-send-email-sboyd@codeaurora.org>

If we're suspended and sched_clock() is called we're going to
read the hardware one more time and throw away that value and
return back the cached value we saved during the suspend
callback. This is wasteful, let's short circuit all that and
return the cached value if we're suspended as early as possible.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/kernel/sched_clock.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
index 48ab64a..29ac613 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -55,9 +55,6 @@ static unsigned long long cyc_to_sched_clock(u32 cyc, u32 mask)
 	u64 epoch_ns;
 	u32 epoch_cyc;
 
-	if (cd.suspended)
-		return cd.epoch_ns;
-
 	/*
 	 * Load the epoch_cyc and epoch_ns atomically.  We do this by
 	 * ensuring that we always write epoch_cyc, epoch_ns and
@@ -174,6 +171,9 @@ unsigned long long __read_mostly (*sched_clock_func)(void) = sched_clock_32;
 
 unsigned long long notrace sched_clock(void)
 {
+	if (cd.suspended)
+		return cd.epoch_ns;
+
 	return sched_clock_func();
 }
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

  parent reply	other threads:[~2013-04-20  0:29 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-18 19:30 [PATCH 1/2] clocksource: arm_arch_timer: unify sched_clock init Rob Herring
2013-04-18 19:30 ` Rob Herring
2013-04-18 19:30 ` [PATCH 2/2] clocksource: arm_arch_timer: add boot and suspend sched_clock offset Rob Herring
2013-04-18 19:30   ` Rob Herring
2013-04-19 14:46   ` Catalin Marinas
2013-04-19 14:46     ` Catalin Marinas
2013-04-19  0:00 ` [PATCH 1/2] clocksource: arm_arch_timer: unify sched_clock init Stephen Boyd
2013-04-19  0:00   ` Stephen Boyd
2013-04-19  1:37   ` Rob Herring
2013-04-19  1:37     ` Rob Herring
2013-04-19 17:34     ` Stephen Boyd
2013-04-19 17:34       ` Stephen Boyd
2013-04-20  0:29     ` [PATCH 0/4] ARM 64 bit sched_clock take #2 Stephen Boyd
2013-04-20  0:29       ` Stephen Boyd
2013-04-20  0:29       ` [PATCH 1/4] ARM: sched_clock: Remove unused needs_suspend member Stephen Boyd
2013-04-20  0:29         ` Stephen Boyd
2013-04-20  0:29       ` Stephen Boyd [this message]
2013-04-20  0:29         ` [PATCH 2/4] ARM: sched_clock: Return suspended count earlier Stephen Boyd
2013-04-20  0:29       ` [PATCH 3/4] ARM: sched_clock: Add support for >32 bit sched_clock Stephen Boyd
2013-04-20  0:29         ` Stephen Boyd
2013-04-20  0:29         ` Stephen Boyd
2013-04-22 10:48         ` Will Deacon
2013-04-22 10:48           ` Will Deacon
2013-04-22 10:48           ` Will Deacon
2013-04-22 15:35           ` Stephen Boyd
2013-04-22 15:35             ` Stephen Boyd
2013-04-22 15:35             ` Stephen Boyd
2013-04-20  0:29       ` [PATCH 4/4] ARM: arch_timer: Move to setup_sched_clock_64() Stephen Boyd
2013-04-20  0:29         ` Stephen Boyd
2013-04-22 15:16       ` [PATCH 0/4] ARM 64 bit sched_clock take #2 Arnd Bergmann
2013-04-22 15:16         ` Arnd Bergmann
2013-04-22 15:34       ` Mark Rutland
2013-04-22 15:34         ` Mark Rutland
2013-04-22 15:34         ` Mark Rutland
2013-04-22 15:36         ` Stephen Boyd
2013-04-22 15:36           ` Stephen Boyd
2013-04-22 15:36           ` Stephen Boyd
2013-04-22 15:51           ` Mark Rutland
2013-04-22 15:51             ` Mark Rutland
2013-04-22 15:51             ` Mark Rutland
2013-04-22 17:00       ` John Stultz
2013-04-22 17:00         ` John Stultz
2013-04-22 20:46         ` Rob Herring
2013-04-22 20:46           ` Rob Herring
2013-04-22 20:46           ` Rob Herring
2013-04-23 16:34           ` Stephen Boyd
2013-04-23 16:34             ` Stephen Boyd
2013-05-01  0:54       ` [PATCH 5/4] sched: Make ARM's sched_clock generic for all architectures Stephen Boyd
2013-05-01  0:54         ` Stephen Boyd
2013-05-01  0:54         ` [PATCH 6/4] arm64: Move to generic sched_clock infrastructure Stephen Boyd
2013-05-01  0:54           ` Stephen Boyd
2013-05-01  9:11           ` Catalin Marinas
2013-05-01  9:11             ` Catalin Marinas
2013-05-01  9:11             ` Catalin Marinas
2013-05-01 14:44             ` Christopher Covington
2013-05-01 14:44               ` Christopher Covington
2013-05-01 14:44               ` Christopher Covington
2013-05-31 20:40         ` [PATCH 5/4] sched: Make ARM's sched_clock generic for all architectures John Stultz
2013-05-31 20:40           ` John Stultz
2013-05-31 22:13           ` Stephen Boyd
2013-05-31 22:13             ` Stephen Boyd
2013-05-31 23:50             ` John Stultz
2013-05-31 23:50               ` John Stultz
2013-04-19 14:45 ` [PATCH 1/2] clocksource: arm_arch_timer: unify sched_clock init Catalin Marinas
2013-04-19 14:45   ` Catalin Marinas

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