Re: [PATCH 2/3] blkio: Add io controller stats like

From: Divyesh Shah
Date: Fri Apr 02 2010 - 14:55:21 EST


On Fri, Apr 2, 2010 at 11:17 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> On Thu, Apr 01, 2010 at 03:01:24PM -0700, Divyesh Shah wrote:
>
> [..]
>> +#define GET_STAT(__VAR, __CONV)                                              \
>> +uint64_t get_##__VAR##_stat(struct blkio_group *blkg, int dummy)     \
>> +{                                                                    \
>> +     uint64_t data = blkg->stats.__VAR;                              \
>> +     if (__CONV)                                                     \
>> +             data = (uint64_t)jiffies_to_msecs(data) * NSEC_PER_MSEC;\
>> +     return data;                                                    \
>> +}
>> +
>
> Hi Divyesh,
>
> I think now you are exporting blkio.time in ns instead of ms?

This is an error.. I should be exporting this in ms. Will send out a
patchset with the change once I also address you other comments in a
bit. Thanks for the review!

> - First of all your are breaking ABI.
> - Secondly, how does that help. You are capturing all your slice used
>  stats in ms. You already lost any ns granularity. What's the point
>  in converting these to ns now?
> - Does user space software really need that fine grained accounting. If
>  this information is used for charging purposes, isn't ms good enough.
>
> Thanks
> Vivek
>
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