[linux-next] delayacct: improve the average delay precision of getdelay tool to microsecond
Commit Message
From: Wang Yong <wang.yong12@zte.com.cn>
Improve the average delay precision of getdelay tool to microsecond.
When using the getdelay tool, it is sometimes found that the average
delay except CPU is not 0, but display is 0, because the precison is too
low. For example, see delay average of SWAP below when using ZRAM.
print delayacct stats ON
PID 32915
CPU count real total virtual total delay total delay average
339202 2793871936 9233585504 7951112 0.000ms
IO count delay total delay average
41 419296904 10ms
SWAP count delay total delay average
242589 1045792384 0ms
This wrong display is misleading, so improve the millisecond precision
of the average delay to microsecond just like CPU. Then user would
get more accurate information of delay time.
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
---
Documentation/accounting/delay-accounting.rst | 14 ++++++-------
.../zh_CN/accounting/delay-accounting.rst | 14 ++++++-------
tools/accounting/getdelays.c | 24 +++++++++++-----------
3 files changed, 26 insertions(+), 26 deletions(-)
--
2.15.2
Comments
On Mon, Feb 13, 2023 at 02:08:08PM +0800, yang.yang29@zte.com.cn wrote:
> From: Wang Yong <wang.yong12@zte.com.cn>
>
> Improve the average delay precision of getdelay tool to microsecond.
> When using the getdelay tool, it is sometimes found that the average
> delay except CPU is not 0, but display is 0, because the precison is too
> low. For example, see delay average of SWAP below when using ZRAM.
>
> print delayacct stats ON
> PID 32915
> CPU count real total virtual total delay total delay average
> 339202 2793871936 9233585504 7951112 0.000ms
> IO count delay total delay average
> 41 419296904 10ms
> SWAP count delay total delay average
> 242589 1045792384 0ms
> This wrong display is misleading, so improve the millisecond precision
> of the average delay to microsecond just like CPU. Then user would
> get more accurate information of delay time.
I'm kinda confused. 0.000ms is same as 0ms, right?
And did you mean accuracy of delay average is to be same as CPU time?
> I'm kinda confused. 0.000ms is same as 0ms, right?
Not really. The types of these two results are different, so the precision of
representation is different.
> And did you mean accuracy of delay average is to be same as CPU time?
Yes.
@@ -109,17 +109,17 @@ Get sum of delays, since system boot, for all pids with tgid 5::
CPU count real total virtual total delay total delay average
8 7000000 6872122 3382277 0.423ms
IO count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
SWAP count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
RECLAIM count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
THRASHING count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
COMPACT count delay total delay average
- 0 0 0ms
- WPCOPY count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
+ WPCOPY count delay total delay average
+ 0 0 0.000ms
Get IO accounting for pid 1, it works only with -p::
@@ -92,17 +92,17 @@ getdelays命令的一般格式::
CPU count real total virtual total delay total delay average
8 7000000 6872122 3382277 0.423ms
IO count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
SWAP count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
RECLAIM count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
THRASHING count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
COMPACT count delay total delay average
- 0 0 0ms
- WPCOPY count delay total delay average
- 0 0 0ms
+ 0 0 0.000ms
+ WPCOPY count delay total delay average
+ 0 0 0.000ms
获取pid为1的IO计数，它只和-p一起使用::
# ./getdelays -i -p 1
@@ -198,17 +198,17 @@ static void print_delayacct(struct taskstats *t)
printf("\n\nCPU %15s%15s%15s%15s%15s\n"
" %15llu%15llu%15llu%15llu%15.3fms\n"
"IO %15s%15s%15s\n"
- " %15llu%15llu%15llums\n"
+ " %15llu%15llu%15.3fms\n"
"SWAP %15s%15s%15s\n"
- " %15llu%15llu%15llums\n"
+ " %15llu%15llu%15.3fms\n"
"RECLAIM %12s%15s%15s\n"
- " %15llu%15llu%15llums\n"
+ " %15llu%15llu%15.3fms\n"
"THRASHING%12s%15s%15s\n"
- " %15llu%15llu%15llums\n"
+ " %15llu%15llu%15.3fms\n"
"COMPACT %12s%15s%15s\n"
- " %15llu%15llu%15llums\n"
+ " %15llu%15llu%15.3fms\n"
"WPCOPY %12s%15s%15s\n"
- " %15llu%15llu%15llums\n",
+ " %15llu%15llu%15.3fms\n",
"count", "real total", "virtual total",
"delay total", "delay average",
(unsigned long long)t->cpu_count,
@@ -219,27 +219,27 @@ static void print_delayacct(struct taskstats *t)
"count", "delay total", "delay average",
(unsigned long long)t->blkio_count,
(unsigned long long)t->blkio_delay_total,
- average_ms(t->blkio_delay_total, t->blkio_count),
+ average_ms((double)t->blkio_delay_total, t->blkio_count),
"count", "delay total", "delay average",
(unsigned long long)t->swapin_count,
(unsigned long long)t->swapin_delay_total,
- average_ms(t->swapin_delay_total, t->swapin_count),
+ average_ms((double)t->swapin_delay_total, t->swapin_count),
"count", "delay total", "delay average",
(unsigned long long)t->freepages_count,
(unsigned long long)t->freepages_delay_total,
- average_ms(t->freepages_delay_total, t->freepages_count),
+ average_ms((double)t->freepages_delay_total, t->freepages_count),
"count", "delay total", "delay average",
(unsigned long long)t->thrashing_count,
(unsigned long long)t->thrashing_delay_total,
- average_ms(t->thrashing_delay_total, t->thrashing_count),
+ average_ms((double)t->thrashing_delay_total, t->thrashing_count),
"count", "delay total", "delay average",
(unsigned long long)t->compact_count,
(unsigned long long)t->compact_delay_total,
- average_ms(t->compact_delay_total, t->compact_count),
+ average_ms((double)t->compact_delay_total, t->compact_count),
"count", "delay total", "delay average",
(unsigned long long)t->wpcopy_count,
(unsigned long long)t->wpcopy_delay_total,
- average_ms(t->wpcopy_delay_total, t->wpcopy_count));
+ average_ms((double)t->wpcopy_delay_total, t->wpcopy_count));
}
static void task_context_switch_counts(struct taskstats *t)