[v2,2/2] tools/power turbostat: do not enforce 1ms

Commit Message

Artem Bityutskiy Aug. 14, 2019, 5:12 p.m. UTC

From: Artem Bityutskiy <[e-mail]>

Turbostat works by taking a snapshot of counters, sleeping, taking another
snapshot, calculating deltas, and printing out the table.

The sleep time is controlled via -i option or by user sending a signal or a
character to stdin. In the latter case, turbostat always adds 1 ms
sleep before it reads the counters, in order to avoid larger imprecisions
in the results in prints.

While the 1 ms delay may be a good idea for a "dumb" user, it is a
problem for an "aware" user. I do thousands and thousands of measurements
over a short period of time (like 2ms), and turbostat unconditionally adds
a 1ms to my interval, so I cannot get what I really need.

This patch removes the unconditional 1ms sleep. This is an expert user
tool, after all, and non-experts will unlikely ever use it in the non-fixed
interval mode anyway, so I think it is OK to remove the 1ms delay.

Signed-off-by: Artem Bityutskiy <[e-mail]>
---
 tools/power/x86/turbostat/turbostat.c | 5 -----
 1 file changed, 5 deletions(-)

---
Changelog:

v2: Clean up commit message.

Patch

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 573230a774cd..57e236187cdb 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -39,7 +39,6 @@  FILE *outf;
 int *fd_percpu;
 struct timeval interval_tv = {5, 0};
 struct timespec interval_ts = {5, 0};
-struct timespec one_msec = {0, 1000000};
 unsigned int num_iterations;
 unsigned int debug;
 unsigned int quiet;
@@ -2986,8 +2985,6 @@  static void signal_handler (int signal)
 			fprintf(stderr, "SIGUSR1\n");
 		break;
 	}
-	/* make sure this manually-invoked interval is at least 1ms long */
-	nanosleep(&one_msec, NULL);
 }
 
 void setup_signal_handler(void)
@@ -3038,8 +3035,6 @@  void do_sleep(void)
 			rest.tv_nsec = (tout.tv_usec % 1000000) * 1000;
 			nanosleep(&rest, NULL);
 		}
-		/* make sure this manually-invoked interval is at least 1ms long */
-		nanosleep(&one_msec, NULL);
 	}
 }