Caching registers value into an array. Got about 4% speed up
of perf_reg_value function for report command processing
dwarf unwind stacks.
Output from report over 1.5 GB data with DWARF unwind stacks:
(TODO fix perf diff)
current code:
6.81% perf.old perf.old [.] perf_reg_value
change:
2.24% perf perf [.] perf_reg_value
And little bit of speed up:
Performance counter stats for './perf.old report -i perf-test.data --stdio':
134,664,011,577 cycles:u # 2.472 GHz
189,677,227,475 instructions:u # 1.41 insns per cycle
54465.096050 task-clock (msec) # 0.998 CPUs utilized
54.598339009 seconds time elapsed
Performance counter stats for './perf report -i perf-test.data --stdio':
124,478,681,672 cycles:u # 2.466 GHz
168,998,379,866 instructions:u # 1.36 insns per cycle
50487.110482 task-clock (msec) # 0.997 CPUs utilized
50.635824229 seconds time elapsed
Cc: Corey Ashford <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jean Pihet <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
---
tools/perf/util/event.h | 5 +++++
tools/perf/util/perf_regs.c | 10 +++++++++-
tools/perf/util/perf_regs.h | 4 +++-
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 38457d4..970d4eb 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -7,6 +7,7 @@
#include "../perf.h"
#include "map.h"
#include "build-id.h"
+#include "perf_regs.h"
struct mmap_event {
struct perf_event_header header;
@@ -87,6 +88,10 @@ struct regs_dump {
u64 abi;
u64 mask;
u64 *regs;
+
+ /* Cached values/mask filled by first register access. */
+ u64 cache_regs[PERF_REGS_MAX];
+ u64 cache_mask;
};
struct stack_dump {
diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
index a3539ef..43168fb 100644
--- a/tools/perf/util/perf_regs.c
+++ b/tools/perf/util/perf_regs.c
@@ -1,11 +1,15 @@
#include <errno.h>
#include "perf_regs.h"
+#include "event.h"
int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
{
int i, idx = 0;
u64 mask = regs->mask;
+ if (regs->cache_mask & (1 << id))
+ goto out;
+
if (!(mask & (1 << id)))
return -EINVAL;
@@ -14,6 +18,10 @@ int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
idx++;
}
- *valp = regs->regs[idx];
+ regs->cache_mask |= (1 << id);
+ regs->cache_regs[id] = regs->regs[idx];
+
+out:
+ *valp = regs->cache_regs[id];
return 0;
}
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index d6e8b6a..80d8ab1 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -2,15 +2,17 @@
#define __PERF_REGS_H
#include "types.h"
-#include "event.h"
#ifdef HAVE_PERF_REGS_SUPPORT
#include <perf_regs.h>
+struct regs_dump;
+
int perf_reg_value(u64 *valp, struct regs_dump *regs, int id);
#else
#define PERF_REGS_MASK 0
+#define PERF_REGS_MAX 0
static inline const char *perf_reg_name(int id __maybe_unused)
{
--
1.8.3.1
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