perf: Cleanup {start,commit,cancel}_txn details
Clarify some of the transactional group scheduling API details and change it so that a successfull ->commit_txn also closes the transaction. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1274803086.5882.1752.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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3af9e85928
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@ -754,7 +754,7 @@ static int power_pmu_enable(struct perf_event *event)
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* skip the schedulability test here, it will be peformed
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* at commit time(->commit_txn) as a whole
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*/
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if (cpuhw->group_flag & PERF_EVENT_TXN_STARTED)
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if (cpuhw->group_flag & PERF_EVENT_TXN)
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goto nocheck;
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if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
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@ -858,7 +858,7 @@ void power_pmu_start_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
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cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
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cpuhw->group_flag |= PERF_EVENT_TXN;
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cpuhw->n_txn_start = cpuhw->n_events;
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}
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@ -871,7 +871,7 @@ void power_pmu_cancel_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
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cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
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cpuhw->group_flag &= ~PERF_EVENT_TXN;
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}
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/*
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@ -897,6 +897,7 @@ int power_pmu_commit_txn(const struct pmu *pmu)
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for (i = cpuhw->n_txn_start; i < n; ++i)
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cpuhw->event[i]->hw.config = cpuhw->events[i];
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cpuhw->group_flag &= ~PERF_EVENT_TXN;
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return 0;
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}
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@ -1005,7 +1005,7 @@ static int sparc_pmu_enable(struct perf_event *event)
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* skip the schedulability test here, it will be peformed
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* at commit time(->commit_txn) as a whole
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*/
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if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
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if (cpuc->group_flag & PERF_EVENT_TXN)
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goto nocheck;
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if (check_excludes(cpuc->event, n0, 1))
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@ -1102,7 +1102,7 @@ static void sparc_pmu_start_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
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cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
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cpuhw->group_flag |= PERF_EVENT_TXN;
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}
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/*
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@ -1114,7 +1114,7 @@ static void sparc_pmu_cancel_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
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cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
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cpuhw->group_flag &= ~PERF_EVENT_TXN;
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}
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/*
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@ -1137,6 +1137,7 @@ static int sparc_pmu_commit_txn(const struct pmu *pmu)
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if (sparc_check_constraints(cpuc->event, cpuc->events, n))
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return -EAGAIN;
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cpuc->group_flag &= ~PERF_EVENT_TXN;
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return 0;
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}
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@ -969,7 +969,7 @@ static int x86_pmu_enable(struct perf_event *event)
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* skip the schedulability test here, it will be peformed
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* at commit time(->commit_txn) as a whole
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*/
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if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
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if (cpuc->group_flag & PERF_EVENT_TXN)
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goto out;
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ret = x86_pmu.schedule_events(cpuc, n, assign);
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@ -1096,7 +1096,7 @@ static void x86_pmu_disable(struct perf_event *event)
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* The events never got scheduled and ->cancel_txn will truncate
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* the event_list.
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*/
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if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
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if (cpuc->group_flag & PERF_EVENT_TXN)
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return;
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x86_pmu_stop(event);
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@ -1388,7 +1388,7 @@ static void x86_pmu_start_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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cpuc->group_flag |= PERF_EVENT_TXN_STARTED;
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cpuc->group_flag |= PERF_EVENT_TXN;
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cpuc->n_txn = 0;
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}
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@ -1401,7 +1401,7 @@ static void x86_pmu_cancel_txn(const struct pmu *pmu)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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cpuc->group_flag &= ~PERF_EVENT_TXN_STARTED;
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cpuc->group_flag &= ~PERF_EVENT_TXN;
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/*
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* Truncate the collected events.
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*/
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@ -1435,11 +1435,7 @@ static int x86_pmu_commit_txn(const struct pmu *pmu)
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*/
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memcpy(cpuc->assign, assign, n*sizeof(int));
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/*
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* Clear out the txn count so that ->cancel_txn() which gets
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* run after ->commit_txn() doesn't undo things.
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*/
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cpuc->n_txn = 0;
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cpuc->group_flag &= ~PERF_EVENT_TXN;
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return 0;
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}
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@ -549,7 +549,10 @@ struct hw_perf_event {
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struct perf_event;
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#define PERF_EVENT_TXN_STARTED 1
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/*
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* Common implementation detail of pmu::{start,commit,cancel}_txn
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*/
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#define PERF_EVENT_TXN 0x1
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/**
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* struct pmu - generic performance monitoring unit
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@ -563,14 +566,28 @@ struct pmu {
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void (*unthrottle) (struct perf_event *event);
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/*
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* group events scheduling is treated as a transaction,
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* add group events as a whole and perform one schedulability test.
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* If test fails, roll back the whole group
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* Group events scheduling is treated as a transaction, add group
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* events as a whole and perform one schedulability test. If the test
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* fails, roll back the whole group
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*/
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/*
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* Start the transaction, after this ->enable() doesn't need
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* to do schedulability tests.
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*/
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void (*start_txn) (const struct pmu *pmu);
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void (*cancel_txn) (const struct pmu *pmu);
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/*
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* If ->start_txn() disabled the ->enable() schedulability test
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* then ->commit_txn() is required to perform one. On success
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* the transaction is closed. On error the transaction is kept
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* open until ->cancel_txn() is called.
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*/
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int (*commit_txn) (const struct pmu *pmu);
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/*
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* Will cancel the transaction, assumes ->disable() is called for
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* each successfull ->enable() during the transaction.
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*/
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void (*cancel_txn) (const struct pmu *pmu);
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};
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/**
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@ -675,7 +675,6 @@ group_sched_in(struct perf_event *group_event,
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struct perf_event *event, *partial_group = NULL;
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const struct pmu *pmu = group_event->pmu;
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bool txn = false;
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int ret;
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if (group_event->state == PERF_EVENT_STATE_OFF)
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return 0;
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@ -703,15 +702,9 @@ group_sched_in(struct perf_event *group_event,
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}
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}
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if (!txn)
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if (!txn || !pmu->commit_txn(pmu))
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return 0;
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ret = pmu->commit_txn(pmu);
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if (!ret) {
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pmu->cancel_txn(pmu);
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return 0;
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}
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group_error:
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/*
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* Groups can be scheduled in as one unit only, so undo any
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