From a4eaf7f14675cb512d69f0c928055e73d0c6d252 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 16 Jun 2010 14:37:10 +0200 Subject: perf: Rework the PMU methods Replace pmu::{enable,disable,start,stop,unthrottle} with pmu::{add,del,start,stop}, all of which take a flags argument. The new interface extends the capability to stop a counter while keeping it scheduled on the PMU. We replace the throttled state with the generic stopped state. This also allows us to efficiently stop/start counters over certain code paths (like IRQ handlers). It also allows scheduling a counter without it starting, allowing for a generic frozen state (useful for rotating stopped counters). The stopped state is implemented in two different ways, depending on how the architecture implemented the throttled state: 1) We disable the counter: a) the pmu has per-counter enable bits, we flip that b) we program a NOP event, preserving the counter state 2) We store the counter state and ignore all read/overflow events Signed-off-by: Peter Zijlstra Cc: paulus Cc: stephane eranian Cc: Robert Richter Cc: Will Deacon Cc: Paul Mundt Cc: Frederic Weisbecker Cc: Cyrill Gorcunov Cc: Lin Ming Cc: Yanmin Cc: Deng-Cheng Zhu Cc: David Miller Cc: Michael Cree LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/ftrace_event.h | 4 ++-- include/linux/perf_event.h | 54 +++++++++++++++++++++++++++++++++----------- 2 files changed, 43 insertions(+), 15 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 5f8ad7bec636..8beabb958f61 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -252,8 +252,8 @@ DECLARE_PER_CPU(struct pt_regs, perf_trace_regs); extern int perf_trace_init(struct perf_event *event); extern void perf_trace_destroy(struct perf_event *event); -extern int perf_trace_enable(struct perf_event *event); -extern void perf_trace_disable(struct perf_event *event); +extern int perf_trace_add(struct perf_event *event, int flags); +extern void perf_trace_del(struct perf_event *event, int flags); extern int ftrace_profile_set_filter(struct perf_event *event, int event_id, char *filter_str); extern void ftrace_profile_free_filter(struct perf_event *event); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 8cafa15af60d..402073c61669 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -538,6 +538,7 @@ struct hw_perf_event { }; #endif }; + int state; local64_t prev_count; u64 sample_period; u64 last_period; @@ -549,6 +550,13 @@ struct hw_perf_event { #endif }; +/* + * hw_perf_event::state flags + */ +#define PERF_HES_STOPPED 0x01 /* the counter is stopped */ +#define PERF_HES_UPTODATE 0x02 /* event->count up-to-date */ +#define PERF_HES_ARCH 0x04 + struct perf_event; /* @@ -564,42 +572,62 @@ struct pmu { int *pmu_disable_count; + /* + * Fully disable/enable this PMU, can be used to protect from the PMI + * as well as for lazy/batch writing of the MSRs. + */ void (*pmu_enable) (struct pmu *pmu); /* optional */ void (*pmu_disable) (struct pmu *pmu); /* optional */ /* + * Try and initialize the event for this PMU. * Should return -ENOENT when the @event doesn't match this PMU. */ int (*event_init) (struct perf_event *event); - int (*enable) (struct perf_event *event); - void (*disable) (struct perf_event *event); - int (*start) (struct perf_event *event); - void (*stop) (struct perf_event *event); +#define PERF_EF_START 0x01 /* start the counter when adding */ +#define PERF_EF_RELOAD 0x02 /* reload the counter when starting */ +#define PERF_EF_UPDATE 0x04 /* update the counter when stopping */ + + /* + * Adds/Removes a counter to/from the PMU, can be done inside + * a transaction, see the ->*_txn() methods. + */ + int (*add) (struct perf_event *event, int flags); + void (*del) (struct perf_event *event, int flags); + + /* + * Starts/Stops a counter present on the PMU. The PMI handler + * should stop the counter when perf_event_overflow() returns + * !0. ->start() will be used to continue. + */ + void (*start) (struct perf_event *event, int flags); + void (*stop) (struct perf_event *event, int flags); + + /* + * Updates the counter value of the event. + */ void (*read) (struct perf_event *event); - void (*unthrottle) (struct perf_event *event); /* * Group events scheduling is treated as a transaction, add * group events as a whole and perform one schedulability test. * If the test fails, roll back the whole group - */ - - /* - * Start the transaction, after this ->enable() doesn't need to + * + * Start the transaction, after this ->add() doesn't need to * do schedulability tests. */ void (*start_txn) (struct pmu *pmu); /* optional */ /* - * If ->start_txn() disabled the ->enable() schedulability test + * If ->start_txn() disabled the ->add() schedulability test * then ->commit_txn() is required to perform one. On success * the transaction is closed. On error the transaction is kept * open until ->cancel_txn() is called. */ int (*commit_txn) (struct pmu *pmu); /* optional */ /* - * Will cancel the transaction, assumes ->disable() is called - * for each successfull ->enable() during the transaction. + * Will cancel the transaction, assumes ->del() is called + * for each successfull ->add() during the transaction. */ void (*cancel_txn) (struct pmu *pmu); /* optional */ }; @@ -680,7 +708,7 @@ struct perf_event { int nr_siblings; int group_flags; struct perf_event *group_leader; - struct pmu *pmu; + struct pmu *pmu; enum perf_event_active_state state; unsigned int attach_state; -- cgit v1.2.3