refscale: Optimize process_durations()

process_durations() is not a hot path, but there is no good reason to
iterate over and over the data already in 'buf'.

Using a seq_buf saves some useless strcat() and the need of a temp buffer.
Data is written directly at the correct place.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Tested-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
This commit is contained in:
Christophe JAILLET 2024-07-21 09:23:46 +02:00 committed by Neeraj Upadhyay
parent 3e49aea71d
commit 4e39bb49c2

View File

@ -28,6 +28,7 @@
#include <linux/rcupdate_trace.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/seq_buf.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/stat.h>
@ -891,32 +892,34 @@ static u64 process_durations(int n)
{
int i;
struct reader_task *rt;
char buf1[64];
struct seq_buf s;
char *buf;
u64 sum = 0;
buf = kmalloc(800 + 64, GFP_KERNEL);
if (!buf)
return 0;
buf[0] = 0;
sprintf(buf, "Experiment #%d (Format: <THREAD-NUM>:<Total loop time in ns>)",
exp_idx);
seq_buf_init(&s, buf, 800 + 64);
seq_buf_printf(&s, "Experiment #%d (Format: <THREAD-NUM>:<Total loop time in ns>)",
exp_idx);
for (i = 0; i < n && !torture_must_stop(); i++) {
rt = &(reader_tasks[i]);
sprintf(buf1, "%d: %llu\t", i, rt->last_duration_ns);
if (i % 5 == 0)
strcat(buf, "\n");
if (strlen(buf) >= 800) {
pr_alert("%s", buf);
buf[0] = 0;
seq_buf_putc(&s, '\n');
if (seq_buf_used(&s) >= 800) {
pr_alert("%s", seq_buf_str(&s));
seq_buf_clear(&s);
}
strcat(buf, buf1);
seq_buf_printf(&s, "%d: %llu\t", i, rt->last_duration_ns);
sum += rt->last_duration_ns;
}
pr_alert("%s\n", buf);
pr_alert("%s\n", seq_buf_str(&s));
kfree(buf);
return sum;