Re: [PATCH 02/14] perf, core: introduce pmu context switch callback
On 02/06/2014 12:01 AM, Stephane Eranian wrote:
> On Fri, Jan 3, 2014 at 6:47 AM, Yan, Zheng wrote:
>> The callback is invoked when process is scheduled in or out. It
>> provides mechanism for later patches to save/store the LBR stack.
>> It can also replace the flush branch stack callback.
>>
> I think you need to say this callback may be invoked on context switches
> with per-thread events attached. As far I understand, the callback cannot
> be invoked for system-wide events.
It's also invoked when there is only system-wide event. (the flush branch stack
case)
Regards
Yan, Zheng
>
>> To avoid unnecessary overhead, the callback is enabled dynamically
>>
>> Signed-off-by: Yan, Zheng
>> ---
>> arch/x86/kernel/cpu/perf_event.c | 7 +
>> arch/x86/kernel/cpu/perf_event.h | 4 +++
>> include/linux/perf_event.h | 8 ++
>> kernel/events/core.c | 60
>> +++-
>> 4 files changed, 78 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/cpu/perf_event.c
>> b/arch/x86/kernel/cpu/perf_event.c
>> index 8e13293..6703d17 100644
>> --- a/arch/x86/kernel/cpu/perf_event.c
>> +++ b/arch/x86/kernel/cpu/perf_event.c
>> @@ -1846,6 +1846,12 @@ static const struct attribute_group
>> *x86_pmu_attr_groups[] = {
>> NULL,
>> };
>>
>> +static void x86_pmu_sched_task(struct perf_event_context *ctx, bool
>> sched_in)
>> +{
>> + if (x86_pmu.sched_task)
>> + x86_pmu.sched_task(ctx, sched_in);
>> +}
>> +
>> static void x86_pmu_flush_branch_stack(void)
>> {
>> if (x86_pmu.flush_branch_stack)
>> @@ -1879,6 +1885,7 @@ static struct pmu pmu = {
>>
>> .event_idx = x86_pmu_event_idx,
>> .flush_branch_stack = x86_pmu_flush_branch_stack,
>> + .sched_task = x86_pmu_sched_task,
>> };
>>
>> void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
>> diff --git a/arch/x86/kernel/cpu/perf_event.h
>> b/arch/x86/kernel/cpu/perf_event.h
>> index 745f6fb..3fdb751 100644
>> --- a/arch/x86/kernel/cpu/perf_event.h
>> +++ b/arch/x86/kernel/cpu/perf_event.h
>> @@ -417,6 +417,8 @@ struct x86_pmu {
>>
>> void(*check_microcode)(void);
>> void(*flush_branch_stack)(void);
>> + void(*sched_task)(struct perf_event_context *ctx,
>> + bool sched_in);
>>
>> /*
>> * Intel Arch Perfmon v2+
>> @@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
>>
>> void intel_ds_init(void);
>>
>> +void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool
>> sched_in);
>> +
> There is no mention of this function anywhere else. Should not be here.
>
>> void intel_pmu_lbr_reset(void);
>>
>> void intel_pmu_lbr_enable(struct perf_event *event);
>> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
>> index 8f4a70f..6a3e603 100644
>> --- a/include/linux/perf_event.h
>> +++ b/include/linux/perf_event.h
>> @@ -251,6 +251,12 @@ struct pmu {
>> * flush branch stack on context-switches (needed in cpu-wide mode)
>> */
>> void (*flush_branch_stack) (void);
>> +
>> + /*
>> +* PMU callback for context-switches. optional
>> +*/
>> + void (*sched_task) (struct perf_event_context *ctx,
>> +bool sched_in);
>> };
>>
>> /**
>> @@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
>> *task);
>> extern void perf_event_print_debug(void);
>> extern void perf_pmu_disable(struct pmu *pmu);
>> extern void perf_pmu_enable(struct pmu *pmu);
>> +extern void perf_sched_cb_disable(struct pmu *pmu);
>> +extern void perf_sched_cb_enable(struct pmu *pmu);
>> extern int perf_event_task_disable(void);
>> extern int perf_event_task_enable(void);
>> extern int perf_event_refresh(struct perf_event *event, int refresh);
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index 89d34f9..d110a23 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -141,6 +141,7 @@ enum event_type_t {
>> struct static_key_deferred perf_sched_events __read_mostly;
>> static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
>> static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
>> +static DEFINE_PER_CPU(int, perf_sched_cb_usages);
>>
>> static atomic_t nr_mmap_events __read_mostly;
>> static atomic_t nr_comm_events __read_mostly;
>> @@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
>> static LIST_HEAD(pmus);
>> static DEFINE_MUTEX(pmus_lock);
>> static struct srcu_struct pmus_srcu;
>> +static struct idr pmu_idr;
>>
>> /*
>> * perf event paranoia level:
>> @@ -2327,6 +2329,57 @@ unlock:
>> }
>> }
>>
>> +void perf_sched_cb_disable(struct pmu *pmu)
>> +{
>> + __get_cpu_var(perf_sched_cb_usages)--;
>> +}
>> +
>> +void perf_sched_cb_enable(struct pmu *pmu)
>> +{
>> +
Re: [PATCH 02/14] perf, core: introduce pmu context switch callback
On Fri, Jan 3, 2014 at 6:47 AM, Yan, Zheng wrote:
> The callback is invoked when process is scheduled in or out. It
> provides mechanism for later patches to save/store the LBR stack.
> It can also replace the flush branch stack callback.
>
I think you need to say this callback may be invoked on context switches
with per-thread events attached. As far I understand, the callback cannot
be invoked for system-wide events.
> To avoid unnecessary overhead, the callback is enabled dynamically
>
> Signed-off-by: Yan, Zheng
> ---
> arch/x86/kernel/cpu/perf_event.c | 7 +
> arch/x86/kernel/cpu/perf_event.h | 4 +++
> include/linux/perf_event.h | 8 ++
> kernel/events/core.c | 60
> +++-
> 4 files changed, 78 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event.c
> b/arch/x86/kernel/cpu/perf_event.c
> index 8e13293..6703d17 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -1846,6 +1846,12 @@ static const struct attribute_group
> *x86_pmu_attr_groups[] = {
> NULL,
> };
>
> +static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
> +{
> + if (x86_pmu.sched_task)
> + x86_pmu.sched_task(ctx, sched_in);
> +}
> +
> static void x86_pmu_flush_branch_stack(void)
> {
> if (x86_pmu.flush_branch_stack)
> @@ -1879,6 +1885,7 @@ static struct pmu pmu = {
>
> .event_idx = x86_pmu_event_idx,
> .flush_branch_stack = x86_pmu_flush_branch_stack,
> + .sched_task = x86_pmu_sched_task,
> };
>
> void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
> diff --git a/arch/x86/kernel/cpu/perf_event.h
> b/arch/x86/kernel/cpu/perf_event.h
> index 745f6fb..3fdb751 100644
> --- a/arch/x86/kernel/cpu/perf_event.h
> +++ b/arch/x86/kernel/cpu/perf_event.h
> @@ -417,6 +417,8 @@ struct x86_pmu {
>
> void(*check_microcode)(void);
> void(*flush_branch_stack)(void);
> + void(*sched_task)(struct perf_event_context *ctx,
> + bool sched_in);
>
> /*
> * Intel Arch Perfmon v2+
> @@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
>
> void intel_ds_init(void);
>
> +void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);
> +
There is no mention of this function anywhere else. Should not be here.
> void intel_pmu_lbr_reset(void);
>
> void intel_pmu_lbr_enable(struct perf_event *event);
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 8f4a70f..6a3e603 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -251,6 +251,12 @@ struct pmu {
> * flush branch stack on context-switches (needed in cpu-wide mode)
> */
> void (*flush_branch_stack) (void);
> +
> + /*
> +* PMU callback for context-switches. optional
> +*/
> + void (*sched_task) (struct perf_event_context *ctx,
> +bool sched_in);
> };
>
> /**
> @@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
> *task);
> extern void perf_event_print_debug(void);
> extern void perf_pmu_disable(struct pmu *pmu);
> extern void perf_pmu_enable(struct pmu *pmu);
> +extern void perf_sched_cb_disable(struct pmu *pmu);
> +extern void perf_sched_cb_enable(struct pmu *pmu);
> extern int perf_event_task_disable(void);
> extern int perf_event_task_enable(void);
> extern int perf_event_refresh(struct perf_event *event, int refresh);
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 89d34f9..d110a23 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -141,6 +141,7 @@ enum event_type_t {
> struct static_key_deferred perf_sched_events __read_mostly;
> static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
> static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
> +static DEFINE_PER_CPU(int, perf_sched_cb_usages);
>
> static atomic_t nr_mmap_events __read_mostly;
> static atomic_t nr_comm_events __read_mostly;
> @@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
> static LIST_HEAD(pmus);
> static DEFINE_MUTEX(pmus_lock);
> static struct srcu_struct pmus_srcu;
> +static struct idr pmu_idr;
>
> /*
> * perf event paranoia level:
> @@ -2327,6 +2329,57 @@ unlock:
> }
> }
>
> +void perf_sched_cb_disable(struct pmu *pmu)
> +{
> + __get_cpu_var(perf_sched_cb_usages)--;
> +}
> +
> +void perf_sched_cb_enable(struct pmu *pmu)
> +{
> + __get_cpu_var(perf_sched_cb_usages)++;
> +}
> +
I think you want to use jump_labels instead of this to make
the callback optional. This is already used all over the place
in the generic code.
> +/*
> + * This function provides the context switch callback to the lower code
> + * layer. It is invoked ONLY when the context switch
Re: [PATCH 02/14] perf, core: introduce pmu context switch callback
On Fri, Jan 3, 2014 at 6:47 AM, Yan, Zheng zheng.z@intel.com wrote:
The callback is invoked when process is scheduled in or out. It
provides mechanism for later patches to save/store the LBR stack.
It can also replace the flush branch stack callback.
I think you need to say this callback may be invoked on context switches
with per-thread events attached. As far I understand, the callback cannot
be invoked for system-wide events.
To avoid unnecessary overhead, the callback is enabled dynamically
Signed-off-by: Yan, Zheng zheng.z@intel.com
---
arch/x86/kernel/cpu/perf_event.c | 7 +
arch/x86/kernel/cpu/perf_event.h | 4 +++
include/linux/perf_event.h | 8 ++
kernel/events/core.c | 60
+++-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c
b/arch/x86/kernel/cpu/perf_event.c
index 8e13293..6703d17 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1846,6 +1846,12 @@ static const struct attribute_group
*x86_pmu_attr_groups[] = {
NULL,
};
+static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
+{
+ if (x86_pmu.sched_task)
+ x86_pmu.sched_task(ctx, sched_in);
+}
+
static void x86_pmu_flush_branch_stack(void)
{
if (x86_pmu.flush_branch_stack)
@@ -1879,6 +1885,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.flush_branch_stack = x86_pmu_flush_branch_stack,
+ .sched_task = x86_pmu_sched_task,
};
void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
diff --git a/arch/x86/kernel/cpu/perf_event.h
b/arch/x86/kernel/cpu/perf_event.h
index 745f6fb..3fdb751 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -417,6 +417,8 @@ struct x86_pmu {
void(*check_microcode)(void);
void(*flush_branch_stack)(void);
+ void(*sched_task)(struct perf_event_context *ctx,
+ bool sched_in);
/*
* Intel Arch Perfmon v2+
@@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
void intel_ds_init(void);
+void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);
+
There is no mention of this function anywhere else. Should not be here.
void intel_pmu_lbr_reset(void);
void intel_pmu_lbr_enable(struct perf_event *event);
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8f4a70f..6a3e603 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -251,6 +251,12 @@ struct pmu {
* flush branch stack on context-switches (needed in cpu-wide mode)
*/
void (*flush_branch_stack) (void);
+
+ /*
+* PMU callback for context-switches. optional
+*/
+ void (*sched_task) (struct perf_event_context *ctx,
+bool sched_in);
};
/**
@@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
*task);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
+extern void perf_sched_cb_disable(struct pmu *pmu);
+extern void perf_sched_cb_enable(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
extern int perf_event_refresh(struct perf_event *event, int refresh);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 89d34f9..d110a23 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -141,6 +141,7 @@ enum event_type_t {
struct static_key_deferred perf_sched_events __read_mostly;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
+static DEFINE_PER_CPU(int, perf_sched_cb_usages);
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
@@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
+static struct idr pmu_idr;
/*
* perf event paranoia level:
@@ -2327,6 +2329,57 @@ unlock:
}
}
+void perf_sched_cb_disable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)--;
+}
+
+void perf_sched_cb_enable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)++;
+}
+
I think you want to use jump_labels instead of this to make
the callback optional. This is already used all over the place
in the generic code.
+/*
+ * This function provides the context switch callback to the lower code
+ * layer. It is invoked ONLY when the context switch callback is enabled.
+ */
+static void perf_pmu_sched_task(struct task_struct *prev,
Re: [PATCH 02/14] perf, core: introduce pmu context switch callback
On 02/06/2014 12:01 AM, Stephane Eranian wrote:
On Fri, Jan 3, 2014 at 6:47 AM, Yan, Zheng zheng.z@intel.com wrote:
The callback is invoked when process is scheduled in or out. It
provides mechanism for later patches to save/store the LBR stack.
It can also replace the flush branch stack callback.
I think you need to say this callback may be invoked on context switches
with per-thread events attached. As far I understand, the callback cannot
be invoked for system-wide events.
It's also invoked when there is only system-wide event. (the flush branch stack
case)
Regards
Yan, Zheng
To avoid unnecessary overhead, the callback is enabled dynamically
Signed-off-by: Yan, Zheng zheng.z@intel.com
---
arch/x86/kernel/cpu/perf_event.c | 7 +
arch/x86/kernel/cpu/perf_event.h | 4 +++
include/linux/perf_event.h | 8 ++
kernel/events/core.c | 60
+++-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c
b/arch/x86/kernel/cpu/perf_event.c
index 8e13293..6703d17 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1846,6 +1846,12 @@ static const struct attribute_group
*x86_pmu_attr_groups[] = {
NULL,
};
+static void x86_pmu_sched_task(struct perf_event_context *ctx, bool
sched_in)
+{
+ if (x86_pmu.sched_task)
+ x86_pmu.sched_task(ctx, sched_in);
+}
+
static void x86_pmu_flush_branch_stack(void)
{
if (x86_pmu.flush_branch_stack)
@@ -1879,6 +1885,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.flush_branch_stack = x86_pmu_flush_branch_stack,
+ .sched_task = x86_pmu_sched_task,
};
void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
diff --git a/arch/x86/kernel/cpu/perf_event.h
b/arch/x86/kernel/cpu/perf_event.h
index 745f6fb..3fdb751 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -417,6 +417,8 @@ struct x86_pmu {
void(*check_microcode)(void);
void(*flush_branch_stack)(void);
+ void(*sched_task)(struct perf_event_context *ctx,
+ bool sched_in);
/*
* Intel Arch Perfmon v2+
@@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
void intel_ds_init(void);
+void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool
sched_in);
+
There is no mention of this function anywhere else. Should not be here.
void intel_pmu_lbr_reset(void);
void intel_pmu_lbr_enable(struct perf_event *event);
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8f4a70f..6a3e603 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -251,6 +251,12 @@ struct pmu {
* flush branch stack on context-switches (needed in cpu-wide mode)
*/
void (*flush_branch_stack) (void);
+
+ /*
+* PMU callback for context-switches. optional
+*/
+ void (*sched_task) (struct perf_event_context *ctx,
+bool sched_in);
};
/**
@@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
*task);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
+extern void perf_sched_cb_disable(struct pmu *pmu);
+extern void perf_sched_cb_enable(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
extern int perf_event_refresh(struct perf_event *event, int refresh);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 89d34f9..d110a23 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -141,6 +141,7 @@ enum event_type_t {
struct static_key_deferred perf_sched_events __read_mostly;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
+static DEFINE_PER_CPU(int, perf_sched_cb_usages);
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
@@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
+static struct idr pmu_idr;
/*
* perf event paranoia level:
@@ -2327,6 +2329,57 @@ unlock:
}
}
+void perf_sched_cb_disable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)--;
+}
+
+void perf_sched_cb_enable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)++;
+}
+
I think you want to use jump_labels instead of this to make
the callback optional. This is already used all over the place
in the generic code.
+/*
+ * This function provides the context
[PATCH 02/14] perf, core: introduce pmu context switch callback
The callback is invoked when process is scheduled in or out. It
provides mechanism for later patches to save/store the LBR stack.
It can also replace the flush branch stack callback.
To avoid unnecessary overhead, the callback is enabled dynamically
Signed-off-by: Yan, Zheng
---
arch/x86/kernel/cpu/perf_event.c | 7 +
arch/x86/kernel/cpu/perf_event.h | 4 +++
include/linux/perf_event.h | 8 ++
kernel/events/core.c | 60 +++-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 8e13293..6703d17 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1846,6 +1846,12 @@ static const struct attribute_group
*x86_pmu_attr_groups[] = {
NULL,
};
+static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
+{
+ if (x86_pmu.sched_task)
+ x86_pmu.sched_task(ctx, sched_in);
+}
+
static void x86_pmu_flush_branch_stack(void)
{
if (x86_pmu.flush_branch_stack)
@@ -1879,6 +1885,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.flush_branch_stack = x86_pmu_flush_branch_stack,
+ .sched_task = x86_pmu_sched_task,
};
void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 745f6fb..3fdb751 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -417,6 +417,8 @@ struct x86_pmu {
void(*check_microcode)(void);
void(*flush_branch_stack)(void);
+ void(*sched_task)(struct perf_event_context *ctx,
+ bool sched_in);
/*
* Intel Arch Perfmon v2+
@@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
void intel_ds_init(void);
+void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);
+
void intel_pmu_lbr_reset(void);
void intel_pmu_lbr_enable(struct perf_event *event);
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8f4a70f..6a3e603 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -251,6 +251,12 @@ struct pmu {
* flush branch stack on context-switches (needed in cpu-wide mode)
*/
void (*flush_branch_stack) (void);
+
+ /*
+* PMU callback for context-switches. optional
+*/
+ void (*sched_task) (struct perf_event_context *ctx,
+bool sched_in);
};
/**
@@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
*task);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
+extern void perf_sched_cb_disable(struct pmu *pmu);
+extern void perf_sched_cb_enable(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
extern int perf_event_refresh(struct perf_event *event, int refresh);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 89d34f9..d110a23 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -141,6 +141,7 @@ enum event_type_t {
struct static_key_deferred perf_sched_events __read_mostly;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
+static DEFINE_PER_CPU(int, perf_sched_cb_usages);
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
@@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
+static struct idr pmu_idr;
/*
* perf event paranoia level:
@@ -2327,6 +2329,57 @@ unlock:
}
}
+void perf_sched_cb_disable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)--;
+}
+
+void perf_sched_cb_enable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)++;
+}
+
+/*
+ * This function provides the context switch callback to the lower code
+ * layer. It is invoked ONLY when the context switch callback is enabled.
+ */
+static void perf_pmu_sched_task(struct task_struct *prev,
+ struct task_struct *next,
+ bool sched_in)
+{
+ struct perf_cpu_context *cpuctx;
+ struct pmu *pmu;
+ unsigned long flags;
+
+ if (prev == next)
+ return;
+
+ local_irq_save(flags);
+
+ rcu_read_lock();
+
+ pmu = idr_find(_idr, PERF_TYPE_RAW);
+
+ if (pmu && pmu->sched_task) {
+ cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+ pmu = cpuctx->ctx.pmu;
+
+ perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+
+ perf_pmu_disable(pmu);
[PATCH 02/14] perf, core: introduce pmu context switch callback
The callback is invoked when process is scheduled in or out. It
provides mechanism for later patches to save/store the LBR stack.
It can also replace the flush branch stack callback.
To avoid unnecessary overhead, the callback is enabled dynamically
Signed-off-by: Yan, Zheng zheng.z@intel.com
---
arch/x86/kernel/cpu/perf_event.c | 7 +
arch/x86/kernel/cpu/perf_event.h | 4 +++
include/linux/perf_event.h | 8 ++
kernel/events/core.c | 60 +++-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 8e13293..6703d17 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1846,6 +1846,12 @@ static const struct attribute_group
*x86_pmu_attr_groups[] = {
NULL,
};
+static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
+{
+ if (x86_pmu.sched_task)
+ x86_pmu.sched_task(ctx, sched_in);
+}
+
static void x86_pmu_flush_branch_stack(void)
{
if (x86_pmu.flush_branch_stack)
@@ -1879,6 +1885,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.flush_branch_stack = x86_pmu_flush_branch_stack,
+ .sched_task = x86_pmu_sched_task,
};
void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 745f6fb..3fdb751 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -417,6 +417,8 @@ struct x86_pmu {
void(*check_microcode)(void);
void(*flush_branch_stack)(void);
+ void(*sched_task)(struct perf_event_context *ctx,
+ bool sched_in);
/*
* Intel Arch Perfmon v2+
@@ -675,6 +677,8 @@ void intel_pmu_pebs_disable_all(void);
void intel_ds_init(void);
+void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);
+
void intel_pmu_lbr_reset(void);
void intel_pmu_lbr_enable(struct perf_event *event);
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8f4a70f..6a3e603 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -251,6 +251,12 @@ struct pmu {
* flush branch stack on context-switches (needed in cpu-wide mode)
*/
void (*flush_branch_stack) (void);
+
+ /*
+* PMU callback for context-switches. optional
+*/
+ void (*sched_task) (struct perf_event_context *ctx,
+bool sched_in);
};
/**
@@ -546,6 +552,8 @@ extern void perf_event_delayed_put(struct task_struct
*task);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
+extern void perf_sched_cb_disable(struct pmu *pmu);
+extern void perf_sched_cb_enable(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
extern int perf_event_refresh(struct perf_event *event, int refresh);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 89d34f9..d110a23 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -141,6 +141,7 @@ enum event_type_t {
struct static_key_deferred perf_sched_events __read_mostly;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
+static DEFINE_PER_CPU(int, perf_sched_cb_usages);
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
@@ -150,6 +151,7 @@ static atomic_t nr_freq_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
+static struct idr pmu_idr;
/*
* perf event paranoia level:
@@ -2327,6 +2329,57 @@ unlock:
}
}
+void perf_sched_cb_disable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)--;
+}
+
+void perf_sched_cb_enable(struct pmu *pmu)
+{
+ __get_cpu_var(perf_sched_cb_usages)++;
+}
+
+/*
+ * This function provides the context switch callback to the lower code
+ * layer. It is invoked ONLY when the context switch callback is enabled.
+ */
+static void perf_pmu_sched_task(struct task_struct *prev,
+ struct task_struct *next,
+ bool sched_in)
+{
+ struct perf_cpu_context *cpuctx;
+ struct pmu *pmu;
+ unsigned long flags;
+
+ if (prev == next)
+ return;
+
+ local_irq_save(flags);
+
+ rcu_read_lock();
+
+ pmu = idr_find(pmu_idr, PERF_TYPE_RAW);
+
+ if (pmu pmu-sched_task) {
+ cpuctx = this_cpu_ptr(pmu-pmu_cpu_context);
+ pmu = cpuctx-ctx.pmu;
+
+ perf_ctx_lock(cpuctx, cpuctx-task_ctx);
+
+
