[PATCH] gstat on SSD

[Alexander Motin]

On 15.11.2014 23:35, Garrett Cooper wrote:
> On Nov 15, 2014, at 8:04, Ranjan1018 . <214748mv at gmail.com> wrote:
>> I am running a pair of servers with SSD. In gstat the default
>> display of operation/ms is only one digit after the comma and
>> there are a lot of R/W operation displayed with the 0.1 value.
>> This simple patch displays  the operation/ms with two decimal
>> digit.
>> 
>> What’s next ? After testing this patch for a day, recording the
>> values in a log file, I have found that some write operation are
>> only 0.02 ms short, on a OCZ Vertex SSD. Probably the next patch
>> is to display micro seconds instead of milli seconds.
>> 
>> Maurizio
>> 
>> FreeBSD 11 gstat.c.patch <http://pastebin.com/B7B8SEy9>
> 
> LGTM, but I don’t have hardware capable of that precision so I
> can’t verify the patch other than build test it and run it for what
> existing cases I have.
> 
> What do you think Alexander?

SSD in my laptop can to 20K simple case IOPS in one stream, that means
~50us time. So I think this patch should not harm. From the other side
these numbers are mostly informational, since any real performance
investigation would require a histogram rather the a single average
number.

-- 
Alexander Motin