From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alan D. Brunelle" Date: Wed, 16 Jul 2008 14:22:30 +0000 Subject: Re: [Patch 0/3] driver data: blktrace pass-through support for device Message-Id: <487E0426.5020107@hp.com> List-Id: References: <1216207494.26621.82.camel@kitka.ibm.com> In-Reply-To: <1216207494.26621.82.camel@kitka.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-btrace@vger.kernel.org Martin Peschke wrote: > 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. > > > Martin Hi Martin - Have you thought about just using blk_add_trace_msg instead? Alan