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authorChristof Schmitt <christof.schmitt@de.ibm.com>2008-05-06 11:00:06 +0200
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-06-05 09:23:44 -0500
commit3a0d9e92356feb60ee4e978355f712366a93f4ef (patch)
treeecc4d53b2120713f80d9b6b664741f4ac7e3344b
parentc9615858a81d2424c78b10a2f689ba24b156937c (diff)
[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>
-rw-r--r--drivers/s390/scsi/zfcp_scsi.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 01687559dc0..4b0c85acb0f 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -778,6 +778,68 @@ struct fc_function_template zfcp_transport_functions = {
.disable_target_scan = 1,
};
+#define ZFCP_DEFINE_LATENCY_ATTR(_name) \
+static ssize_t \
+zfcp_sysfs_unit_##_name##_latency_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) { \
+ struct scsi_device *sdev = to_scsi_device(dev); \
+ struct zfcp_unit *unit = sdev->hostdata; \
+ struct zfcp_latencies *lat = &unit->latencies; \
+ struct zfcp_adapter *adapter = unit->port->adapter; \
+ unsigned long flags; \
+ unsigned long long fsum, fmin, fmax, csum, cmin, cmax, cc; \
+ \
+ spin_lock_irqsave(&lat->lock, flags); \
+ fsum = lat->_name.fabric.sum * adapter->timer_ticks; \
+ fmin = lat->_name.fabric.min * adapter->timer_ticks; \
+ fmax = lat->_name.fabric.max * adapter->timer_ticks; \
+ csum = lat->_name.channel.sum * adapter->timer_ticks; \
+ cmin = lat->_name.channel.min * adapter->timer_ticks; \
+ cmax = lat->_name.channel.max * adapter->timer_ticks; \
+ cc = lat->_name.counter; \
+ spin_unlock_irqrestore(&lat->lock, flags); \
+ \
+ do_div(fsum, 1000); \
+ do_div(fmin, 1000); \
+ do_div(fmax, 1000); \
+ do_div(csum, 1000); \
+ do_div(cmin, 1000); \
+ do_div(cmax, 1000); \
+ \
+ return sprintf(buf, "%llu %llu %llu %llu %llu %llu %llu\n", \
+ fmin, fmax, fsum, cmin, cmax, csum, cc); \
+} \
+static ssize_t \
+zfcp_sysfs_unit_##_name##_latency_store(struct device *dev, \
+ struct device_attribute *attr, \
+ const char *buf, size_t count) \
+{ \
+ struct scsi_device *sdev = to_scsi_device(dev); \
+ struct zfcp_unit *unit = sdev->hostdata; \
+ struct zfcp_latencies *lat = &unit->latencies; \
+ unsigned long flags; \
+ \
+ spin_lock_irqsave(&lat->lock, flags); \
+ lat->_name.fabric.sum = 0; \
+ lat->_name.fabric.min = 0xFFFFFFFF; \
+ lat->_name.fabric.max = 0; \
+ lat->_name.channel.sum = 0; \
+ lat->_name.channel.min = 0xFFFFFFFF; \
+ lat->_name.channel.max = 0; \
+ lat->_name.counter = 0; \
+ spin_unlock_irqrestore(&lat->lock, flags); \
+ \
+ return (ssize_t) count; \
+} \
+static DEVICE_ATTR(_name##_latency, S_IWUSR | S_IRUGO, \
+ zfcp_sysfs_unit_##_name##_latency_show, \
+ zfcp_sysfs_unit_##_name##_latency_store);
+
+ZFCP_DEFINE_LATENCY_ATTR(read);
+ZFCP_DEFINE_LATENCY_ATTR(write);
+ZFCP_DEFINE_LATENCY_ATTR(cmd);
+
/**
* ZFCP_DEFINE_SCSI_ATTR
* @_name: name of show attribute
@@ -808,6 +870,9 @@ static struct device_attribute *zfcp_sysfs_sdev_attrs[] = {
&dev_attr_fcp_lun,
&dev_attr_wwpn,
&dev_attr_hba_id,
+ &dev_attr_read_latency,
+ &dev_attr_write_latency,
+ &dev_attr_cmd_latency,
NULL
};