]> err.no Git - linux-2.6/commit
[SCSI] zfcp: sysfs attributes for fabric and channel latencies
authorChristof Schmitt <christof.schmitt@de.ibm.com>
Tue, 6 May 2008 09:00:06 +0000 (11:00 +0200)
committerJames Bottomley <James.Bottomley@HansenPartnership.com>
Thu, 5 Jun 2008 14:23:44 +0000 (09:23 -0500)
commit3a0d9e92356feb60ee4e978355f712366a93f4ef
treeecc4d53b2120713f80d9b6b664741f4ac7e3344b
parentc9615858a81d2424c78b10a2f689ba24b156937c
[SCSI] zfcp: sysfs attributes for fabric and channel latencies

The latency information is provided on a SCSI device level (LUN)
which can be found at the following location

 /sys/class/scsi_device/<H:C:T:L>/device/cmd_latency
 /sys/class/scsi_device/<H:C:T:L>/device/read_latency
 /sys/class/scsi_device/<H:C:T:L>/device/write_latency

Each sysfs attribute provides the available data: min, max and sum for
fabric and channel latency and the number of requests processed.

An overrun of the variables is neither detected nor treated.  The file
has to be read twice to make a meaningful statement, because only the
differences of the values between the two reads can be used.  A reset
of the values can be achieved by writing to the attribute.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
drivers/s390/scsi/zfcp_scsi.c