Impact: cleanup
Introduce a proper enum for the 3 states of a counter:
PERF_COUNTER_STATE_OFF = -1
PERF_COUNTER_STATE_INACTIVE = 0
PERF_COUNTER_STATE_ACTIVE = 1
and rename counter->active to counter->state and propagate the
changes everywhere.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Rename them to better match up the usual IRQ disable/enable APIs:
hw_perf_disable_all() => hw_perf_save_disable()
hw_perf_restore_ctrl() => hw_perf_restore()
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add new perf-counter type
The 'CPU clock' counter counts the amount of CPU clock time that is
elapsing, in nanoseconds. (regardless of how much of it the task is
spending on a CPU executing)
This counter type is a Linux kernel based abstraction, it is available
even if the hardware does not support native hardware performance counters.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: restructure code, introduce hw_ops driver abstraction
Introduce this abstraction to handle counter details:
struct hw_perf_counter_ops {
void (*hw_perf_counter_enable) (struct perf_counter *counter);
void (*hw_perf_counter_disable) (struct perf_counter *counter);
void (*hw_perf_counter_read) (struct perf_counter *counter);
};
This will be useful to support assymetric hw details, and it will also
be useful to implement "software counters". (Counters that count kernel
managed sw events such as pagefaults, context-switches, wall-clock time
or task-local time.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add group counters
This patch adds the "counter groups" abstraction.
Groups of counters behave much like normal 'single' counters, with a
few semantic and behavioral extensions on top of that.
A counter group is created by creating a new counter with the open()
syscall's group-leader group_fd file descriptor parameter pointing
to another, already existing counter.
Groups of counters are scheduled in and out in one atomic group, and
they are also roundrobin-scheduled atomically.
Counters that are member of a group can also record events with an
(atomic) extended timestamp that extends to all members of the group,
if the record type is set to PERF_RECORD_GROUP.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up new API
Thorough cleanup of the new perf counters API, we now get clean separation
of the various concepts:
- introduce perf_counter_hw_event to separate out the event source details
- move special type flags into separate attributes: PERF_COUNT_NMI,
PERF_COUNT_RAW
- extend the type to u64 and reserve it fully to the architecture in the
raw type case.
And make use of all these changes in the core and x86 perfcounters code.
Also change the syscall signature to:
asmlinkage int sys_perf_counter_open(
struct perf_counter_hw_event *hw_event_uptr __user,
pid_t pid,
int cpu,
int group_fd);
( Note that group_fd is unused for now - it's reserved for the counter
groups abstraction. )
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: change syscall, cleanup
Make use of the new perf_counters event type.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix rare lost events problem
There are CPUs whose performance counters misbehave on CSTATE transitions,
so provide a way to just disable/enable them around deep idle methods.
(hw_perf_enable_all() is cheap on x86.)
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix spurious missed counter wakeups
In the case of NMI events, close a race window that can occur if an NMI
hits counter code that temporarily disables+enables a counter, and the NMI
leaks into the disabled section.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: make perfcounter NMI and IRQ sequence more robust
Make __smp_perf_counter_interrupt() a bit more conservative: first disable
all counters, then read out the status. Most invocations are because there
are real events, so there's no performance impact.
Code flow gets a bit simpler as well this way.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Implement performance counters for x86 Intel CPUs.
It's simplified right now: the PERFMON CPU feature is assumed,
which is available in Core2 and later Intel CPUs.
The design is flexible to be extended to more CPU types as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
