Hi,
On Tue, Mar 17, 2020 at 08:34:48AM -0600, Jens Axboe wrote:
> On 3/17/20 6:53 AM, Feng Tang wrote:
> > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
> > ---
> > lib/gauss.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/gauss.c b/lib/gauss.c
> > index 1d24e187..3f84dbc6 100644
> > --- a/lib/gauss.c
> > +++ b/lib/gauss.c
> > @@ -51,7 +51,7 @@ void gauss_init(struct gauss_state *gs, unsigned long nranges, double dev,
> > gs->nranges = nranges;
> >
> > if (dev != 0.0) {
> > - gs->stddev = ceil((double) (nranges * 100.0) / dev);
> > + gs->stddev = ceil((double)(nranges * dev) / 100.0);
> > if (gs->stddev > nranges / 2)
> > gs->stddev = nranges / 2;
> > }
>
> Looks like I very helpfully did not include a reference to to where
> this is from... Can you expand on the need for the patch?
Thanks for your prompt response!
I tried to run fio with "random_distribution=normal:20" as one
parameter, and didn't notice it has difference with "normal:50",
so I went to read the source code, as the man page says the
deviation ranges from 0 to 100, so this gs->stddev will
always be "nranges/2". Or I misunderstood the man page?
Thanks,
Feng
>
> --
> Jens Axboe
