perf_counter: output objects

Provide a {type,size} header for each output entry.

This should provide extensible output, and the ability to mix multiple streams.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Orig-LKML-Reference: <20090325113316.831607932@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 48212c15b7d6ba66390e16a9897c67d828961388..c256635377d4365e23b4beae924fd703cce3423c 100644 (file)
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -156,6 +156,16 @@ struct perf_counter_mmap_page {
        __u32   data_head;              /* head in the data section */
 };
 
+struct perf_event_header {
+       __u32   type;
+       __u32   size;
+};
+
+enum perf_event_type {
+       PERF_EVENT_IP           = 0,
+       PERF_EVENT_GROUP        = 1,
+};
+
 #ifdef __KERNEL__
 /*
  * Kernel-internal data types and definitions:
@@ -260,6 +270,7 @@ struct perf_counter {
        struct list_head                list_entry;
        struct list_head                event_entry;
        struct list_head                sibling_list;
+       int                             nr_siblings;
        struct perf_counter             *group_leader;
        const struct hw_perf_counter_ops *hw_ops;
 

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 0422fd9bf6273a9540ddb07453d35b103373ebb4..d76e3112d386bd1b89df8b4c6f3a65195583ae2f 100644 (file)
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -75,8 +75,10 @@ list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
         */
        if (counter->group_leader == counter)
                list_add_tail(&counter->list_entry, &ctx->counter_list);
-       else
+       else {
                list_add_tail(&counter->list_entry, &group_leader->sibling_list);
+               group_leader->nr_siblings++;
+       }
 
        list_add_rcu(&counter->event_entry, &ctx->event_list);
 }
@@ -89,6 +91,9 @@ list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
        list_del_init(&counter->list_entry);
        list_del_rcu(&counter->event_entry);
 
+       if (counter->group_leader != counter)
+               counter->group_leader->nr_siblings--;
+
        /*
         * If this was a group counter with sibling counters then
         * upgrade the siblings to singleton counters by adding them
@@ -381,9 +386,11 @@ static int is_software_only_group(struct perf_counter *leader)
 
        if (!is_software_counter(leader))
                return 0;
+
        list_for_each_entry(counter, &leader->sibling_list, list_entry)
                if (!is_software_counter(counter))
                        return 0;
+
        return 1;
 }
 
@@ -1480,6 +1487,9 @@ static void perf_output_copy(struct perf_output_handle *handle,
        handle->offset = offset;
 }
 
+#define perf_output_put(handle, x) \
+       perf_output_copy((handle), &(x), sizeof(x))
+
 static void perf_output_end(struct perf_output_handle *handle, int nmi)
 {
        if (handle->wakeup) {
@@ -1514,34 +1524,53 @@ out:
 static void perf_output_simple(struct perf_counter *counter,
                               int nmi, struct pt_regs *regs)
 {
-       u64 entry;
+       struct {
+               struct perf_event_header header;
+               u64 ip;
+       } event;
 
-       entry = instruction_pointer(regs);
+       event.header.type = PERF_EVENT_IP;
+       event.header.size = sizeof(event);
+       event.ip = instruction_pointer(regs);
 
-       perf_output_write(counter, nmi, &entry, sizeof(entry));
+       perf_output_write(counter, nmi, &event, sizeof(event));
 }
 
-struct group_entry {
-       u64 event;
-       u64 counter;
-};
-
 static void perf_output_group(struct perf_counter *counter, int nmi)
 {
+       struct perf_output_handle handle;
+       struct perf_event_header header;
        struct perf_counter *leader, *sub;
+       unsigned int size;
+       struct {
+               u64 event;
+               u64 counter;
+       } entry;
+       int ret;
+
+       size = sizeof(header) + counter->nr_siblings * sizeof(entry);
+
+       ret = perf_output_begin(&handle, counter, size);
+       if (ret)
+               return;
+
+       header.type = PERF_EVENT_GROUP;
+       header.size = size;
+
+       perf_output_put(&handle, header);
 
        leader = counter->group_leader;
        list_for_each_entry(sub, &leader->sibling_list, list_entry) {
-               struct group_entry entry;
-
                if (sub != counter)
                        sub->hw_ops->read(sub);
 
                entry.event = sub->hw_event.config;
                entry.counter = atomic64_read(&sub->count);
 
-               perf_output_write(counter, nmi, &entry, sizeof(entry));
+               perf_output_put(&handle, entry);
        }
+
+       perf_output_end(&handle, nmi);
 }
 
 void perf_counter_output(struct perf_counter *counter,