From e6dab5ffab59e910ec0e3355f4a6f29f7a7be474 Mon Sep 17 00:00:00 2001 From: Andrew Vagin Date: Wed, 11 Jul 2012 18:14:58 +0400 Subject: perf/trace: Add ability to set a target task for events A few events are interesting not only for a current task. For example, sched_stat_* events are interesting for a task which wakes up. For this reason, it will be good if such events will be delivered to a target task too. Now a target task can be set by using __perf_task(). The original idea and a draft patch belongs to Peter Zijlstra. I need these events for profiling sleep times. sched_switch is used for getting callchains and sched_stat_* is used for getting time periods. These events are combined in user space, then it can be analyzed by perf tools. Inspired-by: Peter Zijlstra Cc: Steven Rostedt Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Steven Rostedt Cc: Arun Sharma Signed-off-by: Andrew Vagin Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1342016098-213063-1-git-send-email-avagin@openvz.org Signed-off-by: Ingo Molnar --- kernel/events/callchain.c | 9 ++++++++- kernel/events/core.c | 30 ++++++++++++++++++++++++++++-- kernel/events/internal.h | 3 ++- 3 files changed, 38 insertions(+), 4 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 6581a040f399..98d4597f43d6 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -153,7 +153,8 @@ put_callchain_entry(int rctx) put_recursion_context(__get_cpu_var(callchain_recursion), rctx); } -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +struct perf_callchain_entry * +perf_callchain(struct perf_event *event, struct pt_regs *regs) { int rctx; struct perf_callchain_entry *entry; @@ -178,6 +179,12 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) } if (regs) { + /* + * Disallow cross-task user callchains. + */ + if (event->ctx->task && event->ctx->task != current) + goto exit_put; + perf_callchain_store(entry, PERF_CONTEXT_USER); perf_callchain_user(entry, regs); } diff --git a/kernel/events/core.c b/kernel/events/core.c index f1cf0edeb39a..b7935fcec7d9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4039,7 +4039,7 @@ void perf_prepare_sample(struct perf_event_header *header, if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; - data->callchain = perf_callchain(regs); + data->callchain = perf_callchain(event, regs); if (data->callchain) size += data->callchain->nr; @@ -5209,7 +5209,8 @@ static int perf_tp_event_match(struct perf_event *event, } void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, - struct pt_regs *regs, struct hlist_head *head, int rctx) + struct pt_regs *regs, struct hlist_head *head, int rctx, + struct task_struct *task) { struct perf_sample_data data; struct perf_event *event; @@ -5228,6 +5229,31 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, perf_swevent_event(event, count, &data, regs); } + /* + * If we got specified a target task, also iterate its context and + * deliver this event there too. + */ + if (task && task != current) { + struct perf_event_context *ctx; + struct trace_entry *entry = record; + + rcu_read_lock(); + ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); + if (!ctx) + goto unlock; + + list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { + if (event->attr.type != PERF_TYPE_TRACEPOINT) + continue; + if (event->attr.config != entry->type) + continue; + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_event(event, count, &data, regs); + } +unlock: + rcu_read_unlock(); + } + perf_swevent_put_recursion_context(rctx); } EXPORT_SYMBOL_GPL(perf_tp_event); diff --git a/kernel/events/internal.h b/kernel/events/internal.h index b0b107f90afc..a096c19f2c2a 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -101,7 +101,8 @@ __output_copy(struct perf_output_handle *handle, } /* Callchain handling */ -extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs); +extern struct perf_callchain_entry * +perf_callchain(struct perf_event *event, struct pt_regs *regs); extern int get_callchain_buffers(void); extern void put_callchain_buffers(void); -- cgit v1.2.3