hwlat-detector: Use trace_clock_local if available
As ktime_get() calls into the timing code which does a read_seq(), it may be affected by other CPUS that touch that lock. To remove this dependency, use the trace_clock_local() which is already exported for module use. If CONFIG_TRACING is enabled, use that as the clock, otherwise use ktime_get(). Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
This commit is contained in:
parent
b35913d046
commit
a24b607e6b
|
@ -51,6 +51,7 @@
|
|||
#include <linux/version.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/trace_clock.h>
|
||||
|
||||
#define BUF_SIZE_DEFAULT 262144UL /* 8K*(sizeof(entry)) */
|
||||
#define BUF_FLAGS (RB_FL_OVERWRITE) /* no block on full */
|
||||
|
@ -211,6 +212,21 @@ static struct sample *buffer_get_sample(struct sample *sample)
|
|||
return sample;
|
||||
}
|
||||
|
||||
#ifndef CONFIG_TRACING
|
||||
#define time_type ktime_t
|
||||
#define time_get() ktime_get()
|
||||
#define time_to_us(x) ktime_to_us(x)
|
||||
#define time_sub(a, b) ktime_sub(a, b)
|
||||
#define init_time(a, b) (a).tv64 = b
|
||||
#define time_u64(a) ((a).tv64)
|
||||
#else
|
||||
#define time_type u64
|
||||
#define time_get() trace_clock_local()
|
||||
#define time_to_us(x) div_u64(x, 1000)
|
||||
#define time_sub(a, b) ((a) - (b))
|
||||
#define init_time(a, b) (a = b)
|
||||
#define time_u64(a) a
|
||||
#endif
|
||||
/**
|
||||
* get_sample - sample the CPU TSC and look for likely hardware latencies
|
||||
* @unused: This is not used but is a part of the stop_machine API
|
||||
|
@ -220,23 +236,23 @@ static struct sample *buffer_get_sample(struct sample *sample)
|
|||
*/
|
||||
static int get_sample(void *unused)
|
||||
{
|
||||
ktime_t start, t1, t2, last_t2;
|
||||
time_type start, t1, t2, last_t2;
|
||||
s64 diff, total = 0;
|
||||
u64 sample = 0;
|
||||
u64 outer_sample = 0;
|
||||
int ret = 1;
|
||||
|
||||
last_t2.tv64 = 0;
|
||||
start = ktime_get(); /* start timestamp */
|
||||
init_time(last_t2, 0);
|
||||
start = time_get(); /* start timestamp */
|
||||
|
||||
do {
|
||||
|
||||
t1 = ktime_get(); /* we'll look for a discontinuity */
|
||||
t2 = ktime_get();
|
||||
t1 = time_get(); /* we'll look for a discontinuity */
|
||||
t2 = time_get();
|
||||
|
||||
if (last_t2.tv64) {
|
||||
if (time_u64(last_t2)) {
|
||||
/* Check the delta from outer loop (t2 to next t1) */
|
||||
diff = ktime_to_us(ktime_sub(t1, last_t2));
|
||||
diff = time_to_us(time_sub(t1, last_t2));
|
||||
/* This shouldn't happen */
|
||||
if (diff < 0) {
|
||||
pr_err(BANNER "time running backwards\n");
|
||||
|
@ -247,10 +263,10 @@ static int get_sample(void *unused)
|
|||
}
|
||||
last_t2 = t2;
|
||||
|
||||
total = ktime_to_us(ktime_sub(t2, start)); /* sample width */
|
||||
total = time_to_us(time_sub(t2, start)); /* sample width */
|
||||
|
||||
/* This checks the inner loop (t1 to t2) */
|
||||
diff = ktime_to_us(ktime_sub(t2, t1)); /* current diff */
|
||||
diff = time_to_us(time_sub(t2, t1)); /* current diff */
|
||||
|
||||
/* This shouldn't happen */
|
||||
if (diff < 0) {
|
||||
|
|
Loading…
Reference in New Issue