On 2011-09-16 05:55, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
>
> Write samples in io_stat does not be counted with rw=randread, vice versa.
> Then, in sum_stat() function, it will cause 0/0 in calculating mean and S,
> and 'nan' is printed. So it should return immediately when src->samples is
> equal to 0.
>
> the error result is as follows:
> write: io=8328.0KB, bw=1582.7KB/s, iops=395 , runt= 5262msec
> clat (usec): min=58 , max=293353 , avg= -nan, stdev= -nan
> lat (usec): min=59 , max=293353 , avg= -nan, stdev= -nan
> bw (KB/s) : min= 92, max= 804, per=-nan%, avg= -nan, stdev= -nan
>
> the configuration file used:
>
> [global]
> direct=1
> ioengine=psync
> bs=4k
> filename=/dev/sdb1
> runtime=5
> group_reporting
> loops=50
>
> [read]
> rw=randread
> numjobs=8
>
> [write]
> rw=randwrite
> numjobs=8
>
> CC: Jens Axboe <jaxboe@xxxxxxxxxxxx>
> CC: Yu-ju Hong <yjhong@xxxxxxxxxx>
> Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> ---
> stat.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/stat.c b/stat.c
> index d2cc775..3662fd9 100644
> --- a/stat.c
> +++ b/stat.c
> @@ -618,6 +618,9 @@ static void sum_stat(struct io_stat *dst, struct io_stat *src, int nr)
> {
> double mean, S;
>
> + if (src->samples == 0)
> + return;
> +
> dst->min_val = min(dst->min_val, src->min_val);
> dst->max_val = max(dst->max_val, src->max_val);
Looks good, applied. Thanks!
--
Jens Axboe
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