From: Catalin Marinas <catalin.marinas@arm.com>
To: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Russell King <linux@arm.linux.org.uk>,
Will Deacon <Will.Deacon@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [PATCH v2 1/3] drivers: clocksource: configure event stream for ARM arch timer
Date: Tue, 23 Jul 2013 11:23:34 +0100 [thread overview]
Message-ID: <20130723102334.GC3748@MacBook-Pro.local> (raw)
In-Reply-To: <1374492082-13686-2-git-send-email-Sudeep.KarkadaNagesha@arm.com>
On Mon, Jul 22, 2013 at 12:21:20PM +0100, Sudeep KarkadaNagesha wrote:
> From: Will Deacon <will.deacon@arm.com>
>
> The ARM architected timer can generate events (used for waking up
> CPUs executing the wfe instruction) at a frequency represented as a
> power-of-2 divisor of the clock rate.
>
> This patch configures the event stream, aiming for a period of 100us
> between events. This can be used to implement wfe-based timeouts for
> userspace locking implementations.
...
> --- a/include/clocksource/arm_arch_timer.h
> +++ b/include/clocksource/arm_arch_timer.h
> @@ -29,6 +29,8 @@
> #define ARCH_TIMER_PHYS_ACCESS 0
> #define ARCH_TIMER_VIRT_ACCESS 1
>
> +#define ARCH_TIMER_EVT_STREAM_FREQ 10000 /* 100us */
BTW, if user-space starts using this, it will become an ABI. Is this the
right frequency?
In addition, do we want to expose this via hwcap? Something like
HWCAP_EVSTR100US?
--
Catalin
WARNING: multiple messages have this Message-ID (diff)
From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/3] drivers: clocksource: configure event stream for ARM arch timer
Date: Tue, 23 Jul 2013 11:23:34 +0100 [thread overview]
Message-ID: <20130723102334.GC3748@MacBook-Pro.local> (raw)
In-Reply-To: <1374492082-13686-2-git-send-email-Sudeep.KarkadaNagesha@arm.com>
On Mon, Jul 22, 2013 at 12:21:20PM +0100, Sudeep KarkadaNagesha wrote:
> From: Will Deacon <will.deacon@arm.com>
>
> The ARM architected timer can generate events (used for waking up
> CPUs executing the wfe instruction) at a frequency represented as a
> power-of-2 divisor of the clock rate.
>
> This patch configures the event stream, aiming for a period of 100us
> between events. This can be used to implement wfe-based timeouts for
> userspace locking implementations.
...
> --- a/include/clocksource/arm_arch_timer.h
> +++ b/include/clocksource/arm_arch_timer.h
> @@ -29,6 +29,8 @@
> #define ARCH_TIMER_PHYS_ACCESS 0
> #define ARCH_TIMER_VIRT_ACCESS 1
>
> +#define ARCH_TIMER_EVT_STREAM_FREQ 10000 /* 100us */
BTW, if user-space starts using this, it will become an ABI. Is this the
right frequency?
In addition, do we want to expose this via hwcap? Something like
HWCAP_EVSTR100US?
--
Catalin
next prev parent reply other threads:[~2013-07-23 10:24 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-18 17:06 [PATCH 0/4] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-06-18 17:06 ` Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 1/4] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-06-18 17:07 ` Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 2/4] ARM: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-06-18 17:07 ` Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 3/4] ARM/ARM64: arch_timer: remove __cpuinit attribute for arch_counter_set_user_access Sudeep KarkadaNagesha
2013-06-18 17:07 ` Sudeep KarkadaNagesha
2013-06-18 17:58 ` Sudeep KarkadaNagesha
2013-06-18 17:58 ` Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 4/4] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-06-18 17:07 ` Sudeep KarkadaNagesha
2013-07-02 16:09 ` Jon Medhurst (Tixy)
2013-07-02 16:09 ` Jon Medhurst (Tixy)
2013-07-02 17:24 ` Sudeep KarkadaNagesha
2013-07-02 17:24 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 0/3] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-07-22 11:21 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 1/3] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-07-22 11:21 ` Sudeep KarkadaNagesha
2013-07-23 10:23 ` Catalin Marinas [this message]
2013-07-23 10:23 ` Catalin Marinas
2013-07-23 10:33 ` Will Deacon
2013-07-23 10:33 ` Will Deacon
2013-07-23 11:12 ` Catalin Marinas
2013-07-23 11:12 ` Catalin Marinas
2013-07-25 9:45 ` [PATCH v3 " Sudeep KarkadaNagesha
2013-07-25 9:45 ` Sudeep KarkadaNagesha
2013-08-12 13:32 ` Sudeep KarkadaNagesha
2013-08-12 13:32 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 2/3] ARM: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-07-22 11:21 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 3/3] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-07-22 11:21 ` Sudeep KarkadaNagesha
2013-08-02 9:32 ` [PATCH v2 0/3] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-08-02 9:32 ` Sudeep KarkadaNagesha
2013-08-02 9:48 ` Daniel Lezcano
2013-08-02 9:48 ` Daniel Lezcano
2013-08-02 9:55 ` Sudeep KarkadaNagesha
2013-08-02 9:55 ` Sudeep KarkadaNagesha
2013-08-02 12:12 ` Daniel Lezcano
2013-08-02 12:12 ` Daniel Lezcano
2013-08-05 16:25 ` Sudeep KarkadaNagesha
2013-08-05 16:25 ` Sudeep KarkadaNagesha
2013-08-06 8:09 ` Daniel Lezcano
2013-08-06 8:09 ` Daniel Lezcano
2013-08-06 9:01 ` Sudeep KarkadaNagesha
2013-08-06 9:01 ` Sudeep KarkadaNagesha
2013-08-12 13:16 ` Daniel Lezcano
2013-08-12 13:16 ` Daniel Lezcano
2013-08-13 17:29 ` [PATCH v3 0/6] " Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 1/6] ARM/ARM64: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-14 8:50 ` Daniel Lezcano
2013-08-14 8:50 ` Daniel Lezcano
2013-08-14 9:03 ` Marc Zyngier
2013-08-14 9:03 ` Marc Zyngier
2013-08-14 9:23 ` Daniel Lezcano
2013-08-14 9:23 ` Daniel Lezcano
2013-08-13 17:29 ` [PATCH v3 2/6] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 3/6] ARM: arch_timer: configure and enable event stream Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 4/6] ARM64: " Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-20 13:27 ` Will Deacon
2013-08-20 13:27 ` Will Deacon
2013-08-20 14:27 ` Sudeep KarkadaNagesha
2013-08-20 14:27 ` Sudeep KarkadaNagesha
2013-08-20 16:16 ` Will Deacon
2013-08-20 16:16 ` Will Deacon
2013-08-20 16:23 ` Sudeep KarkadaNagesha
2013-08-20 16:23 ` Sudeep KarkadaNagesha
2013-08-20 17:08 ` Sudeep KarkadaNagesha
2013-08-20 17:08 ` Sudeep KarkadaNagesha
2013-08-21 17:52 ` Will Deacon
2013-08-21 17:52 ` Will Deacon
2013-08-13 17:29 ` [PATCH v3 5/6] drivers: clocksource: enable hwcaps for event stream on ARM arch timer Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 6/6] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-08-13 17:29 ` Sudeep KarkadaNagesha
2013-08-14 9:08 ` [PATCH v3 0/6] ARM/ARM64 architected timer updates Daniel Lezcano
2013-08-14 9:08 ` Daniel Lezcano
2013-08-14 9:17 ` Sudeep KarkadaNagesha
2013-08-14 9:17 ` Sudeep KarkadaNagesha
2013-08-14 10:51 ` Daniel Lezcano
2013-08-14 10:51 ` Daniel Lezcano
2013-08-14 11:03 ` Sudeep KarkadaNagesha
2013-08-14 11:03 ` Sudeep KarkadaNagesha
2013-08-14 15:00 ` Daniel Lezcano
2013-08-14 15:00 ` Daniel Lezcano
2013-08-20 17:14 ` Sudeep KarkadaNagesha
2013-08-20 17:14 ` Sudeep KarkadaNagesha
2013-08-23 9:26 ` Catalin Marinas
2013-08-23 9:26 ` Catalin Marinas
2013-08-23 9:57 ` Sudeep KarkadaNagesha
2013-08-23 9:57 ` Sudeep KarkadaNagesha
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