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From: Vivek Goyal <vgoyal@redhat.com>
To: Divyesh Shah <dpshah@google.com>
Cc: jens.axboe@oracle.com, linux-kernel@vger.kernel.org,
	nauman@google.com, ctalbott@google.com
Subject: Re: [PATCH 2/3] blkio: Add io controller stats like
Date: Fri, 2 Apr 2010 14:17:54 -0400	[thread overview]
Message-ID: <20100402181754.GC3516@redhat.com> (raw)
In-Reply-To: <20100401220109.2843.36040.stgit@austin.mtv.corp.google.com>

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? 

- 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

  parent reply	other threads:[~2010-04-02 18:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-01 22:00 [PATCH 0/3] blkio: IO controller stats Divyesh Shah
2010-04-01 22:01 ` [PATCH 1/3] blkio: Remove per-cfqq nr_sectors as we'll be passing Divyesh Shah
2010-04-01 22:01 ` [PATCH 2/3] blkio: Add io controller stats like Divyesh Shah
2010-04-02 18:10   ` Vivek Goyal
2010-04-02 20:53     ` Divyesh Shah
2010-04-05 14:45       ` Vivek Goyal
2010-04-05 22:16         ` Divyesh Shah
2010-04-02 18:17   ` Vivek Goyal [this message]
2010-04-02 18:54     ` Divyesh Shah
2010-04-01 22:01 ` [PATCH 3/3] blkio: Increment the blkio cgroup stats for real now Divyesh Shah
2010-04-02 19:10   ` Vivek Goyal
2010-04-02 23:36     ` Divyesh Shah
2010-04-05 15:12       ` Vivek Goyal
2010-04-05 16:53         ` Divyesh Shah
2010-04-05 17:29           ` Vivek Goyal
2010-04-05 22:06             ` Divyesh Shah
2010-04-02  6:45 ` [PATCH 0/3] blkio: IO controller stats Jens Axboe

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