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Message-ID: <4FDB25B6.2040909@linux.vnet.ibm.com>
Date: Fri, 15 Jun 2012 17:38:22 +0530
From: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
To: shuox.liu@...el.com
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"Brown, Len" <len.brown@...el.com>,
"Zhang, Yanmin" <yanmin.zhang@...el.com>,
"Andrew J. Schorr" <aschorr@...emetry-investments.com>
Subject: Re: [PATCH] cpuidle: move field disable from per-driver to per-cpu
On 06/14/2012 08:22 AM, ShuoX Liu wrote:
> From: ShuoX Liu <shuox.liu@...el.com>
>
> Andrew J.Schorr raises a question. When he changes the disable setting
> on a single CPU, it affects all the other CPUs. Basically, currently,
> the disable field is per-driver instead of per-cpu. All the C states of
> the same driver are shared by all CPU in the same machine.
>
> Below patch changes field disable to per-cpu, so we could set this
> separately for each cpu.
>
This would help us have asymmetric C-states on cpus.
> Reported-by: Andrew J.Schorr <aschorr@...emetry-investments.com>
> Reviewed-by: Yanmin Zhang <yanmin_zhang@...el.com>
> Signed-off-by: ShuoX Liu <shuox.liu@...el.com>
Acked-by: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
> ---
> drivers/cpuidle/cpuidle.c | 1 -
> drivers/cpuidle/governors/menu.c | 5 +++--
> drivers/cpuidle/sysfs.c | 21 ++++++++++++---------
> include/linux/cpuidle.h | 2 +-
> 4 files changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index d90519c..04e4b76 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -265,7 +265,6 @@ static void poll_idle_init(struct cpuidle_driver *drv)
> state->power_usage = -1;
> state->flags = 0;
> state->enter = poll_idle;
> - state->disable = 0;
> }
> #else
> static void poll_idle_init(struct cpuidle_driver *drv) {}
> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> index 0633575..8391d93 100644
> --- a/drivers/cpuidle/governors/menu.c
> +++ b/drivers/cpuidle/governors/menu.c
> @@ -281,7 +281,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
> * unless the timer is happening really really soon.
> */
> if (data->expected_us > 5 &&
> - drv->states[CPUIDLE_DRIVER_STATE_START].disable == 0)
> + dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
> data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
>
> /*
> @@ -290,8 +290,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
> */
> for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
> struct cpuidle_state *s = &drv->states[i];
> + struct cpuidle_state_usage *su = &dev->states_usage[i];
>
> - if (s->disable)
> + if (su->disable)
> continue;
> if (s->target_residency > data->predicted_us)
> continue;
> diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> index 88032b4..5f809e3 100644
> --- a/drivers/cpuidle/sysfs.c
> +++ b/drivers/cpuidle/sysfs.c
> @@ -217,7 +217,8 @@ struct cpuidle_state_attr {
> struct attribute attr;
> ssize_t (*show)(struct cpuidle_state *, \
> struct cpuidle_state_usage *, char *);
> - ssize_t (*store)(struct cpuidle_state *, const char *, size_t);
> + ssize_t (*store)(struct cpuidle_state *, \
> + struct cpuidle_state_usage *, const char *, size_t);
> };
>
> #define define_one_state_ro(_name, show) \
> @@ -233,21 +234,22 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
> return sprintf(buf, "%u\n", state->_name);\
> }
>
> -#define define_store_state_function(_name) \
> +#define define_store_state_ull_function(_name) \
> static ssize_t store_state_##_name(struct cpuidle_state *state, \
> + struct cpuidle_state_usage *state_usage, \
> const char *buf, size_t size) \
> { \
> - long value; \
> + unsigned long long value; \
> int err; \
> if (!capable(CAP_SYS_ADMIN)) \
> return -EPERM; \
> - err = kstrtol(buf, 0, &value); \
> + err = kstrtoull(buf, 0, &value); \
> if (err) \
> return err; \
> if (value) \
> - state->disable = 1; \
> + state_usage->_name = 1; \
> else \
> - state->disable = 0; \
> + state_usage->_name = 0; \
> return size; \
> }
>
> @@ -273,8 +275,8 @@ define_show_state_ull_function(usage)
> define_show_state_ull_function(time)
> define_show_state_str_function(name)
> define_show_state_str_function(desc)
> -define_show_state_function(disable)
> -define_store_state_function(disable)
> +define_show_state_ull_function(disable)
> +define_store_state_ull_function(disable)
>
> define_one_state_ro(name, show_state_name);
> define_one_state_ro(desc, show_state_desc);
> @@ -318,10 +320,11 @@ static ssize_t cpuidle_state_store(struct kobject *kobj,
> {
> int ret = -EIO;
> struct cpuidle_state *state = kobj_to_state(kobj);
> + struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
> struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
>
> if (cattr->store)
> - ret = cattr->store(state, buf, size);
> + ret = cattr->store(state, state_usage, buf, size);
>
> return ret;
> }
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 6c26a3d..8570012 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -34,6 +34,7 @@ struct cpuidle_driver;
> struct cpuidle_state_usage {
> void *driver_data;
>
> + unsigned long long disable;
> unsigned long long usage;
> unsigned long long time; /* in US */
> };
> @@ -46,7 +47,6 @@ struct cpuidle_state {
> unsigned int exit_latency; /* in US */
> int power_usage; /* in mW */
> unsigned int target_residency; /* in US */
> - unsigned int disable;
>
> int (*enter) (struct cpuidle_device *dev,
> struct cpuidle_driver *drv,
--
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