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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] tools/xenalyze: Allow automatic resizing of sample buffers
commit 7f5c8075364776eb139bbd421ad443ae9e4465dc
Author: George Dunlap <george.dunlap@xxxxxxxxxx>
AuthorDate: Mon Aug 8 10:42:50 2016 +0100
Commit: George Dunlap <george.dunlap@xxxxxxxxxx>
CommitDate: Tue Aug 9 15:44:57 2016 +0100
tools/xenalyze: Allow automatic resizing of sample buffers
Rather than have large fixed-size buffers, start with smaller buffers
and allow them to grow as needed (doubling each time), with a fairly
large maximum. Allow this maximum to be set by a command-line
parameter.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
tools/xentrace/xenalyze.c | 93 +++++++++++++++++++++++++++++++++--------------
1 file changed, 66 insertions(+), 27 deletions(-)
diff --git a/tools/xentrace/xenalyze.c b/tools/xentrace/xenalyze.c
index d65a727..11763a8 100644
--- a/tools/xentrace/xenalyze.c
+++ b/tools/xentrace/xenalyze.c
@@ -44,7 +44,8 @@ struct mread_ctrl;
#define QHZ_FROM_HZ(_hz) (((_hz) << 10)/ 1000000000)
#define ADDR_SPACE_BITS 48
-#define DEFAULT_SAMPLE_SIZE 10240
+#define DEFAULT_SAMPLE_SIZE 1024
+#define DEFAULT_SAMPLE_MAX 1024*1024*32
#define DEFAULT_INTERVAL_LENGTH 1000
struct array_struct {
@@ -187,7 +188,7 @@ struct {
unsigned long long histogram_interrupt_increment;
int interrupt_eip_enumeration_vector;
int default_guest_paging_levels;
- int sample_size;
+ int sample_size, sample_max;
enum error_level tolerance; /* Tolerate up to this level of error */
struct {
tsc_t cycles;
@@ -257,6 +258,7 @@ struct {
.cpu_qhz = QHZ_FROM_HZ(DEFAULT_CPU_HZ),
.default_guest_paging_levels = 2,
.sample_size = DEFAULT_SAMPLE_SIZE,
+ .sample_max = DEFAULT_SAMPLE_MAX,
.tolerance = ERR_SANITY,
.interval = { .msec = DEFAULT_INTERVAL_LENGTH },
};
@@ -275,7 +277,7 @@ struct interval_element {
};
struct cycle_summary {
- int event_count, count;
+ int event_count, count, sample_size;
unsigned long long cycles;
long long *sample;
struct interval_element interval;
@@ -2203,28 +2205,49 @@ static inline double summary_percent_global(struct
cycle_summary *s) {
}
static inline void update_cycles(struct cycle_summary *s, long long c) {
-/* We don't know ahead of time how many samples there are, and working
- * with dynamic stuff is a pain, and unnecessary. This algorithm will
- * generate a sample set that approximates an even sample. We can
- * then take the percentiles on this, and get an approximate value. */
s->event_count++;
if (!c)
return;
if(opt.sample_size) {
- int lap = (s->count/opt.sample_size)+1,
- index =s->count % opt.sample_size;
- if((index - (lap/3))%lap == 0) {
- if(!s->sample) {
- s->sample = malloc(sizeof(*s->sample) * opt.sample_size);
- if(!s->sample) {
- fprintf(stderr, "%s: malloc failed!\n", __func__);
- error(ERR_SYSTEM, NULL);
- }
+ if (s->count >= s->sample_size
+ && (s->count == 0
+ || opt.sample_max == 0
+ || s->sample_size < opt.sample_max)) {
+ int new_size;
+ void * new_sample = NULL;
+
+ new_size = s->sample_size << 1;
+
+ if (new_size == 0)
+ new_size = opt.sample_size;
+
+ if (opt.sample_max != 0 && new_size > opt.sample_max)
+ new_size = opt.sample_max;
+
+ new_sample = realloc(s->sample, sizeof(*s->sample) * new_size);
+
+ if (new_sample) {
+ s->sample = new_sample;
+ s->sample_size = new_size;
}
- s->sample[index]=c;
}
+
+ if (s->count < s->sample_size) {
+ s->sample[s->count]=c;
+ } else {
+ /*
+ * If we run out of space for samples, start taking only a
+ * subset of samples.
+ */
+ int lap, index;
+ lap = (s->count/s->sample_size)+1;
+ index =s->count % s->sample_size;
+ if((index - (lap/3))%lap == 0) {
+ s->sample[index]=c;
+ }
+ }
}
s->count++;
s->cycles += c;
@@ -2248,8 +2271,8 @@ static inline void print_cpu_affinity(struct
cycle_summary *s, char *p) {
if ( opt.sample_size ) {
long long p5, p50, p95;
int data_size = s->count;
- if(data_size > opt.sample_size)
- data_size = opt.sample_size;
+ if(data_size > s->sample_size)
+ data_size = s->sample_size;
p50 = percentile(s->sample, data_size, 50);
p5 = percentile(s->sample, data_size, 5);
@@ -2280,8 +2303,8 @@ static inline void print_cycle_percent_summary(struct
cycle_summary *s,
long long p5, p50, p95;
int data_size = s->count;
- if(data_size > opt.sample_size)
- data_size = opt.sample_size;
+ if(data_size > s->sample_size)
+ data_size = s->sample_size;
p50 = self_weighted_percentile(s->sample, data_size, 50);
p5 = self_weighted_percentile(s->sample, data_size, 5);
@@ -2312,8 +2335,8 @@ static inline void print_cycle_summary(struct
cycle_summary *s, char *p) {
long long p5, p50, p95;
int data_size = s->count;
- if(data_size > opt.sample_size)
- data_size = opt.sample_size;
+ if(data_size > s->sample_size)
+ data_size = s->sample_size;
p50 = self_weighted_percentile(s->sample, data_size, 50);
p5 = self_weighted_percentile(s->sample, data_size, 5);
@@ -2335,8 +2358,8 @@ static inline void print_cycle_summary(struct
cycle_summary *s, char *p) {
if ( opt.sample_size ) { \
unsigned long long p5, p50, p95; \
int data_size=(_s).count; \
- if(data_size > opt.sample_size) \
- data_size=opt.sample_size; \
+ if(data_size > (_s).sample_size) \
+ data_size=(_s).sample_size; \
p50=percentile((_s).sample, data_size, 50); \
p5=percentile((_s).sample, data_size, 5); \
p95=percentile((_s).sample, data_size, 95); \
@@ -9801,6 +9824,7 @@ enum {
OPT_SHOW_DEFAULT_DOMAIN_SUMMARY,
OPT_MMIO_ENUMERATION_SKIP_VGA,
OPT_SAMPLE_SIZE,
+ OPT_SAMPLE_MAX,
OPT_REPORT_PCPU,
/* Guest info */
OPT_DEFAULT_GUEST_PAGING_LEVELS,
@@ -9983,6 +10007,14 @@ error_t cmd_parser(int key, char *arg, struct
argp_state *state)
argp_usage(state);
break;
}
+ case OPT_SAMPLE_MAX:
+ {
+ char * inval;
+ opt.sample_max = (int)strtol(arg, &inval, 0);
+ if( inval == arg )
+ argp_usage(state);
+ break;
+ }
case OPT_MMIO_ENUMERATION_SKIP_VGA:
{
char * inval;
@@ -10520,8 +10552,15 @@ const struct argp_option cmd_opts[] = {
.key = OPT_SAMPLE_SIZE,
.arg = "size",
.group = OPT_GROUP_SUMMARY,
- .doc = "Keep [size] samples for percentile purposes. Enter 0 to " \
- "disable. Default 10240.", },
+ .doc = "Start with [size] samples for percentile purposes. Enter 0 to" \
+ "disable. Default 1024.", },
+
+ { .name = "sample-max",
+ .key = OPT_SAMPLE_MAX,
+ .arg = "size",
+ .group = OPT_GROUP_SUMMARY,
+ .doc = "Do not allow sample to grow beyond [size] samples for
percentile"\
+ " purposes. Enter 0 for no limit.", },
{ .name = "summary",
.key = OPT_SUMMARY,
--
generated by git-patchbot for /home/xen/git/xen.git#master
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