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authorPeter Zijlstra <peterz@infradead.org>2015-01-14 14:18:11 +0200
committerIngo Molnar <mingo@kernel.org>2015-04-02 17:13:46 +0200
commit45bfb2e50471abbbfd83d40d28c986078b0d24ff (patch)
treef06f2176a2ef51315387f492a3f1b85efe91f2bb /include/linux/perf_event.h
parente8c6deac69629c0cb97c3d3272f8631ef17f8f0f (diff)
perf: Add AUX area to ring buffer for raw data streams
This patch introduces "AUX space" in the perf mmap buffer, intended for exporting high bandwidth data streams to userspace, such as instruction flow traces. AUX space is a ring buffer, defined by aux_{offset,size} fields in the user_page structure, and read/write pointers aux_{head,tail}, which abide by the same rules as data_* counterparts of the main perf buffer. In order to allocate/mmap AUX, userspace needs to set up aux_offset to such an offset that will be greater than data_offset+data_size and aux_size to be the desired buffer size. Both need to be page aligned. Then, same aux_offset and aux_size should be passed to mmap() call and if everything adds up, you should have an AUX buffer as a result. Pages that are mapped into this buffer also come out of user's mlock rlimit plus perf_event_mlock_kb allowance. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kaixu Xia <kaixu.xia@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Robert Richter <rric@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@infradead.org Cc: adrian.hunter@intel.com Cc: kan.liang@intel.com Cc: markus.t.metzger@intel.com Cc: mathieu.poirier@linaro.org Link: http://lkml.kernel.org/r/1421237903-181015-3-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r--include/linux/perf_event.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 401554074de9..5a94f6d6fa91 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -284,6 +284,18 @@ struct pmu {
* Return the count value for a counter.
*/
u64 (*count) (struct perf_event *event); /*optional*/
+
+ /*
+ * Set up pmu-private data structures for an AUX area
+ */
+ void *(*setup_aux) (int cpu, void **pages,
+ int nr_pages, bool overwrite);
+ /* optional */
+
+ /*
+ * Free pmu-private AUX data structures
+ */
+ void (*free_aux) (void *aux); /* optional */
};
/**
@@ -862,6 +874,11 @@ static inline bool needs_branch_stack(struct perf_event *event)
return event->attr.branch_sample_type != 0;
}
+static inline bool has_aux(struct perf_event *event)
+{
+ return event->pmu->setup_aux;
+}
+
extern int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size);
extern void perf_output_end(struct perf_output_handle *handle);