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authorArjan van de Ven <arjan@infradead.org>2009-09-25 12:25:56 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2009-11-03 18:04:17 +0100
commitfb0459d75c1d0a4ba3cafdd2c754e7486968a676 (patch)
tree3e7a112cbf2feb144b3e1abbc5dfb186f77b8b50 /include/linux/perf_event.h
parent0f8f86c7bdd1c954fbe153af437a0d91a6c5721a (diff)
perf/core: Provide a kernel-internal interface to get to performance counters
There are reasons for kernel code to ask for, and use, performance counters. For example, in CPU freq governors this tends to be a good idea, but there are other examples possible as well of course. This patch adds the needed bits to do enable this functionality; they have been tested in an experimental cpufreq driver that I'm working on, and the changes are all that I needed to access counters properly. [fweisbec@gmail.com: added pid to perf_event_create_kernel_counter so that we can profile a particular task too TODO: Have a better error reporting, don't just return NULL in fail case.] v2: Remove the wrong comment about the fact perf_event_create_kernel_counter must be called from a kernel thread. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: "K.Prasad" <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Jiri Slaby <jirislaby@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Avi Kivity <avi@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jan Kiszka <jan.kiszka@web.de> Cc: Avi Kivity <avi@redhat.com> LKML-Reference: <20090925122556.2f8bd939@infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r--include/linux/perf_event.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index df9d964c15fc..fa151d49a2ee 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -744,6 +744,12 @@ extern int hw_perf_group_sched_in(struct perf_event *group_leader,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx, int cpu);
extern void perf_event_update_userpage(struct perf_event *event);
+extern int perf_event_release_kernel(struct perf_event *event);
+extern struct perf_event *
+perf_event_create_kernel_counter(struct perf_event_attr *attr,
+ int cpu,
+ pid_t pid);
+extern u64 perf_event_read_value(struct perf_event *event);
struct perf_sample_data {
u64 type;