From 3a0d9e92356feb60ee4e978355f712366a93f4ef Mon Sep 17 00:00:00 2001 From: Christof Schmitt Date: Tue, 6 May 2008 11:00:06 +0200 Subject: [PATCH] [SCSI] zfcp: sysfs attributes for fabric and channel latencies MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The latency information is provided on a SCSI device level (LUN) which can be found at the following location  /sys/class/scsi_device//device/cmd_latency  /sys/class/scsi_device//device/read_latency  /sys/class/scsi_device//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 Signed-off-by: Christof Schmitt Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_scsi.c | 65 +++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) 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 }; -- 2.41.1