perf_counter: add more context information
Change the callchain context entries to u16, so as to gain some space.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094517.457320003@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 e22ab47..f9d5cf0 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -507,10 +507,10 @@
extern void perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file);
-#define MAX_STACK_DEPTH 254
+#define MAX_STACK_DEPTH 255
struct perf_callchain_entry {
- u32 nr, hv, kernel, user;
+ u16 nr, hv, kernel, user;
u64 ip[MAX_STACK_DEPTH];
};
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 2a5d4f5..727624d 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1657,9 +1657,7 @@
* Callchain support -- arch specific
*/
-struct perf_callchain_entry *
-__attribute__((weak))
-perf_callchain(struct pt_regs *regs)
+__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
{
return NULL;
}
@@ -1819,7 +1817,7 @@
callchain = perf_callchain(regs);
if (callchain) {
- callchain_size = (2 + callchain->nr) * sizeof(u64);
+ callchain_size = (1 + callchain->nr) * sizeof(u64);
header.type |= __PERF_EVENT_CALLCHAIN;
header.size += callchain_size;