Re: [Patch] SCSI statistics

Martin Peschke
2006-09-19T16:33:26Z

Arjan van de Ven wrote:
> On Mon, 2006-09-18 at 13:20 +0200, Martin Peschke wrote:
>> This patch makes the SCSI mid layer report statistics data, i.e. request
>> sizes, request latencies, request results and queue utilisation.
>> For sample output please see below. This data is only gathered if these
>> statistics have been enabled by users at run time (default is off).
>>
>> 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.
>>
>> Patch is against 2.6.18-rc6-mm2, as it requires the statistics
>> infrastructure patches.
>
>
> wouldn't this be nicer as a block level functionality?

I won't mind as long as the data closely resembles the actual
I/O traffic to and from devices.