Re: [Patch 0/3] driver data: blktrace pass-through support for

[Martin Peschke <mpeschke@linux.vnet.ibm.com>]

Hi Jens,
this one might have slipped through your fingers.

This small extension would be really useful for us to complement
blktrace data.

What do you think - yes or no, or maybe? 

Thanks,
Martin


On Sun, 2008-10-05 at 15:07 +0200, Martin Peschke wrote:
> Hi Jens,
> may I ask what you think about this approach? Would you consider
> including the following patch series in blktrace?
> 
> Here is a discussion dating back to the first time I have posted these
> patches:
> http://marc.info/?l=linux-btrace&m\x121620751101386&w=2
> 
> 
> Thanks,
> Martin
> 
> 
> 
> 
> Low-level device drivers might have additional data which complements
> blktrace data. For example, zfcp, a SCSI HBA driver, is capable of
> obtaining additional latency information per request from HBAs. Those
> latencies allow to further break down the overall D2C request latency
> provided by blktrace.
> 
> We propose an additional trace for blktrace, called "driver data". It is
> a sort of small binary blob, which contains a low-level driver specific
> struct. Blktrace would be able to filter this trace (-a option) and
> include it within its binary output. A small device driver specific tool
> on top of blktrace would then analyze "driver data" traces.
> 
> Patch 1/3 makes the blktrace kernel code provide blk_add_driver_data()
> for use by device drivers.
> 
> Patch 2/3 adds support for driver data traces to blktrace tools.
> 
> Patch 3/3 makes zfcp provide additional request latency and queue
> utilization data through blktrace.
> 
> 
> Patches are against scsi-misc and blktrace git.
> 
> 
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