Re: [Patch 0/2] blkiomon: I/O monitor based on blktrace data

["Alan D. Brunelle" <Alan.Brunelle@hp.com>]

Martin Peschke wrote:
> On Wed, 2008-07-16 at 09:28 -0400, Alan D. Brunelle wrote:
>> Martin Peschke wrote:
>>> In order to analyse I/O performance problems which could be reported by
>>> customers we want to provide a little monitoring tool. Primarily, we
>>> would like to be able look at a history of request size and request
>>> latency histograms per device.
>>>
>>> The D and C traces provided by blktrace are exactly what we need for
>>> that purpose. So, running blktrace with appropriate filters (-a option)
>>> makes this approach feasible.
>>>
>>> Patch 1/2 allows users to get binary output from blkparse on stdout.
>>>
>>> Patch 2/2 contains blkiomon, an I/O monitoring tool, which reads
>>> blkparse data from stdin and which periodically writes I/O statistics.
>>>
>>> I would like to contribute this little tool to the blktrace source tree.
>>> I think it would complement blkparse and btt quite well.
>>>
>>> Martin
>> Hi Martin -
>>
>> Is there some reason why you don't just parse the textual output from
>> blkparse itself? [I believe that's what Chris Mason does w/ his
>> seekwatcher for example.]
> 
> Hi Alan,
> we would like to spend as few CPU cycles as possible.
> 
> Having a little c-program consuming binary data is less expensive than
> having blkparse generate textual output which would be parsed by some
> script.
> 
> This is a monitoring tool, and there might be millions of requests.

Hi Martin -

Haven't had time to think this through, but if blktrace is sending
binary data to blkparse, why not just replace blkparse w/ blkiomon?
Taking data directly from blktrace itself?

Alan