The following changes since commit 01423eae85a071ff6acee870edd696c7929723ba:
clock: ensure that we re-init if the clocksource changes from the default (2012-12-14 20:37:06 +0100)
are available in the git repository at:
git://git.kernel.dk/fio.git master
Jens Axboe (4):
cpu clock: add independent test for monotonic/sane TSC
gettime: locking fix and debug check for identical sequence
gettime: include per-cpu clock calibration in cpu clock test
Add --cpuclock-test and clocksource= option help
HOWTO | 16 ++++++
README | 1 +
fio.1 | 21 ++++++++
gettime.c | 172 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gettime.h | 1 +
init.c | 12 ++++-
6 files changed, 222 insertions(+), 1 deletions(-)
---
Diff of recent changes:
diff --git a/HOWTO b/HOWTO
index b349620..0930f33 100644
--- a/HOWTO
+++ b/HOWTO
@@ -1262,6 +1262,22 @@ percentile_list=float_list Overwrite the default list of percentiles
the values of completion latency below which 99.5% and
99.9% of the observed latencies fell, respectively.
+clocksource=str Use the given clocksource as the base of timing. The
+ supported options are:
+
+ gettimeofday gettimeofday(2)
+
+ clock_gettime clock_gettime(2)
+
+ cpu Internal CPU clock source
+
+ cpu is the preferred clocksource if it is reliable, as it
+ is very fast (and fio is heavy on time calls). Fio will
+ automatically use this clocksource if it's supported and
+ considered reliable on the system it is running on, unless
+ another clocksource is specifically set. For x86/x86-64 CPUs,
+ this means supporting TSC Invariant.
+
gtod_reduce=bool Enable all of the gettimeofday() reducing options
(disable_clat, disable_slat, disable_bw) plus reduce
precision of the timeout somewhat to really shrink
diff --git a/README b/README
index ceac385..7c4552d 100644
--- a/README
+++ b/README
@@ -129,6 +129,7 @@ $ fio
--terse-version=type Terse version output format (default 3, or 2 or 4).
--version Print version info and exit
--help Print this page
+ --cpuclock-test Perform test/validation of CPU clock
--cmdhelp=cmd Print command help, "all" for all of them
--enghelp=engine Print ioengine help, or list available ioengines
--enghelp=engine,cmd Print help for an ioengine cmd
diff --git a/fio.1 b/fio.1
index b7abc4b..22c32fd 100644
--- a/fio.1
+++ b/fio.1
@@ -1027,6 +1027,27 @@ given time in milliseconds.
.BI disk_util \fR=\fPbool
Generate disk utilization statistics if the platform supports it. Default: true.
.TP
+.BI clocksource \fR=\fPstr
+Use the given clocksource as the base of timing. The supported options are:
+.RS
+.TP
+.B gettimeofday
+gettimeofday(2)
+.TP
+.B clock_gettime
+clock_gettime(2)
+.TP
+.B cpu
+Internal CPU clock source
+.TP
+.RE
+.P
+\fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast
+(and fio is heavy on time calls). Fio will automatically use this clocksource
+if it's supported and considered reliable on the system it is running on,
+unless another clocksource is specifically set. For x86/x86-64 CPUs, this
+means supporting TSC Invariant.
+.TP
.BI gtod_reduce \fR=\fPbool
Enable all of the gettimeofday() reducing options (disable_clat, disable_slat,
disable_bw) plus reduce precision of the timeout somewhat to really shrink the
diff --git a/gettime.c b/gettime.c
index 9f23e3f..f5be6bd 100644
--- a/gettime.c
+++ b/gettime.c
@@ -11,6 +11,7 @@
#include "smalloc.h"
#include "hash.h"
+#include "os/os.h"
#ifdef ARCH_HAVE_CPU_CLOCK
static unsigned long cycles_per_usec;
@@ -347,3 +348,174 @@ unsigned long time_since_now(struct timeval *s)
{
return mtime_since_now(s) / 1000;
}
+
+#if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK)
+
+#define CLOCK_ENTRIES 100000
+
+struct clock_entry {
+ unsigned long seq;
+ unsigned long tsc;
+ unsigned long cpu;
+};
+
+struct clock_thread {
+ pthread_t thread;
+ int cpu;
+ pthread_mutex_t lock;
+ pthread_mutex_t started;
+ uint64_t *seq;
+ struct clock_entry *entries;
+};
+
+static inline uint64_t atomic64_inc_return(uint64_t *seq)
+{
+ return 1 + __sync_fetch_and_add(seq, 1);
+}
+
+static void *clock_thread_fn(void *data)
+{
+ struct clock_thread *t = data;
+ struct clock_entry *c;
+ os_cpu_mask_t cpu_mask;
+ int i;
+
+ memset(&cpu_mask, 0, sizeof(cpu_mask));
+ fio_cpu_set(&cpu_mask, t->cpu);
+
+ if (fio_setaffinity(gettid(), cpu_mask) == -1) {
+ log_err("clock setaffinity failed\n");
+ return (void *) 1;
+ }
+
+ pthread_mutex_lock(&t->lock);
+ pthread_mutex_unlock(&t->started);
+
+ c = &t->entries[0];
+ for (i = 0; i < CLOCK_ENTRIES; i++, c++) {
+ uint64_t seq, tsc;
+
+ c->cpu = t->cpu;
+ do {
+ seq = atomic64_inc_return(t->seq);
+ tsc = get_cpu_clock();
+ } while (seq != *t->seq);
+
+ c->seq = seq;
+ c->tsc = tsc;
+ }
+
+ log_info("cs: cpu%3d: %lu clocks seen\n", t->cpu, t->entries[CLOCK_ENTRIES - 1].tsc - t->entries[0].tsc);
+ return NULL;
+}
+
+static int clock_cmp(const void *p1, const void *p2)
+{
+ const struct clock_entry *c1 = p1;
+ const struct clock_entry *c2 = p2;
+
+ if (c1->seq == c2->seq)
+ log_err("cs: bug in atomic sequence!\n");
+
+ return c1->seq - c2->seq;
+}
+
+int fio_monotonic_clocktest(void)
+{
+ struct clock_thread *threads;
+ unsigned int nr_cpus = cpus_online();
+ struct clock_entry *entries;
+ unsigned long tentries, failed;
+ uint64_t seq = 0;
+ int i;
+
+ fio_debug |= 1U << FD_TIME;
+ calibrate_cpu_clock();
+ fio_debug &= ~(1U << FD_TIME);
+
+ threads = malloc(nr_cpus * sizeof(struct clock_thread));
+ tentries = CLOCK_ENTRIES * nr_cpus;
+ entries = malloc(tentries * sizeof(struct clock_entry));
+
+ log_info("cs: Testing %u CPUs\n", nr_cpus);
+
+ for (i = 0; i < nr_cpus; i++) {
+ struct clock_thread *t = &threads[i];
+
+ t->cpu = i;
+ t->seq = &seq;
+ t->entries = &entries[i * CLOCK_ENTRIES];
+ pthread_mutex_init(&t->lock, NULL);
+ pthread_mutex_init(&t->started, NULL);
+ pthread_mutex_lock(&t->lock);
+ pthread_create(&t->thread, NULL, clock_thread_fn, t);
+ }
+
+ for (i = 0; i < nr_cpus; i++) {
+ struct clock_thread *t = &threads[i];
+
+ pthread_mutex_lock(&t->started);
+ }
+
+ for (i = 0; i < nr_cpus; i++) {
+ struct clock_thread *t = &threads[i];
+
+ pthread_mutex_unlock(&t->lock);
+ }
+
+ for (failed = i = 0; i < nr_cpus; i++) {
+ struct clock_thread *t = &threads[i];
+ void *ret;
+
+ pthread_join(t->thread, &ret);
+ if (ret)
+ failed++;
+ }
+ free(threads);
+
+ if (failed) {
+ log_err("Clocksource test: %u threads failed\n", failed);
+ goto err;
+ }
+
+ qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp);
+
+ for (failed = i = 0; i < tentries; i++) {
+ struct clock_entry *prev, *this = &entries[i];
+
+ if (!i) {
+ prev = this;
+ continue;
+ }
+
+ if (prev->tsc > this->tsc) {
+ uint64_t diff = prev->tsc - this->tsc;
+
+ log_info("cs: CPU clock mismatch (diff=%lu):\n", diff);
+ log_info("\t CPU%3lu: TSC=%lu, SEQ=%lu\n", prev->cpu, prev->tsc, prev->seq);
+ log_info("\t CPU%3lu: TSC=%lu, SEQ=%lu\n", this->cpu, this->tsc, this->seq);
+ failed++;
+ }
+
+ prev = this;
+ }
+
+ if (failed)
+ log_info("cs: Failed: %lu\n", failed);
+ else
+ log_info("cs: Pass!\n");
+
+err:
+ free(entries);
+ return !!failed;
+}
+
+#else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */
+
+int fio_monotonic_clocktest(void)
+{
+ log_info("cs: current platform does not support CPU clocks\n");
+ return 0;
+}
+
+#endif
diff --git a/gettime.h b/gettime.h
index 64651a1..8ca3791 100644
--- a/gettime.h
+++ b/gettime.h
@@ -15,6 +15,7 @@ extern void fio_gettime(struct timeval *, void *);
extern void fio_gtod_init(void);
extern void fio_clock_init(void);
extern int fio_start_gtod_thread(void);
+extern int fio_monotonic_clocktest(void);
extern struct timeval *fio_tv;
diff --git a/init.c b/init.c
index e90d735..e7b3303 100644
--- a/init.c
+++ b/init.c
@@ -208,6 +208,11 @@ static struct option l_opts[FIO_NR_OPTIONS] = {
.val = 'C',
},
{
+ .name = (char *) "cpuclock-test",
+ .has_arg = no_argument,
+ .val = 'T',
+ },
+ {
.name = NULL,
},
};
@@ -1255,6 +1260,7 @@ static void usage(const char *name)
printf(" --terse-version=x\tSet terse version output format to 'x'\n");
printf(" --version\t\tPrint version info and exit\n");
printf(" --help\t\tPrint this page\n");
+ printf(" --cpuclock-test\tPerform test/validation of CPU clock\n");
printf(" --cmdhelp=cmd\t\tPrint command help, \"all\" for all of"
" them\n");
printf(" --enghelp=engine\tPrint ioengine help, or list"
@@ -1275,7 +1281,7 @@ static void usage(const char *name)
printf(" --daemonize=pidfile\tBackground fio server, write pid to file\n");
printf(" --client=hostname\tTalk to remote backend fio server at hostname\n");
printf("\nFio was written by Jens Axboe <jens.axboe@xxxxxxxxxx>");
- printf("\n Jens Axboe <jaxboe@xxxxxxxxxxxx>\n");
+ printf("\n Jens Axboe <jaxboe@xxxxxxxxxxxx>\n");
}
#ifdef FIO_INC_DEBUG
@@ -1621,6 +1627,10 @@ int parse_cmd_line(int argc, char *argv[])
optind++;
}
break;
+ case 'T':
+ do_exit++;
+ exit_val = fio_monotonic_clocktest();
+ break;
default:
do_exit++;
exit_val = 1;
--
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