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Message-ID: <tip-ee8ff2070444f88524ef89555e3996c8be44170d@git.kernel.org>
Date: Wed, 25 Mar 2009 12:07:11 GMT
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, paulus@...ba.org, hpa@...or.com,
mingo@...hat.com, a.p.zijlstra@...llo.nl, efault@....de,
arjan@...radead.org, tglx@...utronix.de, fengguang.wu@...el.com,
mingo@...e.hu
Subject: [tip:perfcounters/core] perf_counter: kerneltop: output event support
Commit-ID: ee8ff2070444f88524ef89555e3996c8be44170d
Gitweb: http://git.kernel.org/tip/ee8ff2070444f88524ef89555e3996c8be44170d
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Wed, 25 Mar 2009 12:30:27 +0100
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 25 Mar 2009 13:02:53 +0100
perf_counter: kerneltop: output event support
Teach kerneltop about the new output ABI.
XXX: anybody fancy integrating the PID/TID data into the output?
Bump the mmap_data pages a little because we bloated the output and
have to be more careful about overruns with structured data.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Mike Galbraith <efault@....de>
Cc: Arjan van de Ven <arjan@...radead.org>
Cc: Wu Fengguang <fengguang.wu@...el.com>
LKML-Reference: <20090325113317.192910290@...llo.nl>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
Documentation/perf_counter/kerneltop.c | 65 +++++++++++++++++++++++++++++---
1 files changed, 59 insertions(+), 6 deletions(-)
diff --git a/Documentation/perf_counter/kerneltop.c b/Documentation/perf_counter/kerneltop.c
index 3e45bf6..fda1438 100644
--- a/Documentation/perf_counter/kerneltop.c
+++ b/Documentation/perf_counter/kerneltop.c
@@ -134,6 +134,11 @@
#endif
#define unlikely(x) __builtin_expect(!!(x), 0)
+#define min(x, y) ({ \
+ typeof(x) _min1 = (x); \
+ typeof(y) _min2 = (y); \
+ (void) (&_min1 == &_min2); \
+ _min1 < _min2 ? _min1 : _min2; })
asmlinkage int sys_perf_counter_open(
struct perf_counter_hw_event *hw_event_uptr __user,
@@ -178,7 +183,7 @@ static int nr_cpus = 0;
static int nmi = 1;
static int group = 0;
static unsigned int page_size;
-static unsigned int mmap_pages = 4;
+static unsigned int mmap_pages = 16;
static char *vmlinux;
@@ -1147,28 +1152,75 @@ static void mmap_read(struct mmap_data *md)
unsigned int head = mmap_read_head(md);
unsigned int old = md->prev;
unsigned char *data = md->base + page_size;
+ int diff;
gettimeofday(&this_read, NULL);
- if (head - old > md->mask) {
+ /*
+ * If we're further behind than half the buffer, there's a chance
+ * the writer will bite our tail and screw up the events under us.
+ *
+ * If we somehow ended up ahead of the head, we got messed up.
+ *
+ * In either case, truncate and restart at head.
+ */
+ diff = head - old;
+ if (diff > md->mask / 2 || diff < 0) {
struct timeval iv;
unsigned long msecs;
timersub(&this_read, &last_read, &iv);
msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
- fprintf(stderr, "WARNING: failed to keep up with mmap data. Last read %lu msecs ago.\n", msecs);
+ fprintf(stderr, "WARNING: failed to keep up with mmap data."
+ " Last read %lu msecs ago.\n", msecs);
+ /*
+ * head points to a known good entry, start there.
+ */
old = head;
}
last_read = this_read;
for (; old != head;) {
- __u64 *ptr = (__u64 *)&data[old & md->mask];
- old += sizeof(__u64);
+ struct event_struct {
+ struct perf_event_header header;
+ __u64 ip;
+ __u32 pid, tid;
+ } *event = (struct event_struct *)&data[old & md->mask];
+ struct event_struct event_copy;
+
+ unsigned int size = event->header.size;
+
+ /*
+ * Event straddles the mmap boundary -- header should always
+ * be inside due to u64 alignment of output.
+ */
+ if ((old & md->mask) + size != ((old + size) & md->mask)) {
+ unsigned int offset = old;
+ unsigned int len = sizeof(*event), cpy;
+ void *dst = &event_copy;
+
+ do {
+ cpy = min(md->mask + 1 - (offset & md->mask), len);
+ memcpy(dst, &data[offset & md->mask], cpy);
+ offset += cpy;
+ dst += cpy;
+ len -= cpy;
+ } while (len);
+
+ event = &event_copy;
+ }
- process_event(*ptr, md->counter);
+ old += size;
+
+ switch (event->header.type) {
+ case PERF_EVENT_IP:
+ case PERF_EVENT_IP | __PERF_EVENT_TID:
+ process_event(event->ip, md->counter);
+ break;
+ }
}
md->prev = old;
@@ -1214,6 +1266,7 @@ int main(int argc, char *argv[])
hw_event.irq_period = event_count[counter];
hw_event.record_type = PERF_RECORD_IRQ;
hw_event.nmi = nmi;
+ hw_event.include_tid = 1;
fd[i][counter] = sys_perf_counter_open(&hw_event, tid, cpu, group_fd, 0);
if (fd[i][counter] < 0) {
--
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