Messages in this thread | | | Date | Mon, 23 Oct 2006 13:37:29 +0200 | From | Jens Axboe <> | Subject | Re: [Patch 0/5] I/O statistics through request queues |
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On Sat, Oct 21 2006, Martin Peschke wrote: > This patch set makes the block layer maintain statistics for request > queues. Resulting data closely resembles the actual I/O traffic to a > device, as the block layer takes hints from block device drivers when a > request is being issued as well as when it is about to complete. > > It is crucial (for us) to be able to look at such kernel level data in > case of customer situations. It allows us to determine what kind of > requests might be involved in performance situations. This information > helps to understand whether one faces a device issue or a Linux issue. > Not being able to tap into performance data is regarded as a big minus > by some enterprise customers, who are reluctant to use Linux SCSI > support or Linux. > > Statistics data includes: > - request sizes (read + write), > - residual bytes of partially completed requests (read + write), > - request latencies (read + write), > - request retries (read + write), > - request concurrency,
Question - what part of this does blktrace currently not do? In case it's missing something, why not add it there instead of putting new trace code in?
-- Jens Axboe
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