[SCSI] zfcp: Track fabric and channel latencies provided by FCP adapter

Add the infrastructure to retrieve the fabric and channel latencies
from FSF commands for each SCSI command that has been processed. For
each unit, the sum, min, max and number of requests is tracked.

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>

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 8c7e2b778ef1a18fc012c7f80a7429c01c5f4d2f..d23027a2f2f06736adc62a15d108592d019dfc32 100644 (file)
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -847,6 +847,14 @@ zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
        /* mark unit unusable as long as sysfs registration is not complete */
        atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 
+       spin_lock_init(&unit->latencies.lock);
+       unit->latencies.write.channel.min = 0xFFFFFFFF;
+       unit->latencies.write.fabric.min = 0xFFFFFFFF;
+       unit->latencies.read.channel.min = 0xFFFFFFFF;
+       unit->latencies.read.fabric.min = 0xFFFFFFFF;
+       unit->latencies.cmd.channel.min = 0xFFFFFFFF;
+       unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
+
        if (device_register(&unit->sysfs_device)) {
                kfree(unit);
                return NULL;

diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index bda8c77b22daf6160235f3199b93c9953c4b4d51..306fcd0cae310bb8e25778de2d410dce50157787 100644 (file)
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -708,6 +708,24 @@ struct zfcp_erp_action {
        struct timer_list timer;
 };
 
+struct fsf_latency_record {
+       u32 min;
+       u32 max;
+       u64 sum;
+};
+
+struct latency_cont {
+       struct fsf_latency_record channel;
+       struct fsf_latency_record fabric;
+       u64 counter;
+};
+
+struct zfcp_latencies {
+       struct latency_cont read;
+       struct latency_cont write;
+       struct latency_cont cmd;
+       spinlock_t lock;
+};
 
 struct zfcp_adapter {
        struct list_head        list;              /* list of adapters */
@@ -723,6 +741,7 @@ struct zfcp_adapter {
        u32                     adapter_features;  /* FCP channel features */
        u32                     connection_features; /* host connection features */
         u32                    hardware_version;  /* of FCP channel */
+       u16                     timer_ticks;       /* time int for a tick */
        struct Scsi_Host        *scsi_host;        /* Pointer to mid-layer */
        struct list_head        port_list_head;    /* remote port list */
        struct list_head        port_remove_lh;    /* head of ports to be
@@ -822,6 +841,7 @@ struct zfcp_unit {
         struct scsi_device     *device;        /* scsi device struct pointer */
        struct zfcp_erp_action erp_action;     /* pending error recovery */
         atomic_t               erp_counter;
+       struct zfcp_latencies   latencies;
 };
 
 /* FSF request */

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index b2ea4ea051f582009a9dace7d8f6a77109271f0c..1e7136483c1b24d3a49cfff235109adba06940a2 100644 (file)
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -2005,6 +2005,7 @@ zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *fsf_req, int xchg_ok)
                fc_host_supported_classes(shost) =
                                FC_COS_CLASS2 | FC_COS_CLASS3;
                adapter->hydra_version = bottom->adapter_type;
+               adapter->timer_ticks = bottom->timer_interval;
                if (fc_host_permanent_port_name(shost) == -1)
                        fc_host_permanent_port_name(shost) =
                                fc_host_port_name(shost);
@@ -3649,6 +3650,46 @@ zfcp_fsf_send_fcp_command_task_management(struct zfcp_adapter *adapter,
        return fsf_req;
 }
 
+static void zfcp_fsf_update_lat(struct fsf_latency_record *lat_rec, u32 lat)
+{
+       lat_rec->sum += lat;
+       if (lat_rec->min > lat)
+               lat_rec->min = lat;
+       if (lat_rec->max < lat)
+               lat_rec->max = lat;
+}
+
+static void zfcp_fsf_req_latency(struct zfcp_fsf_req *fsf_req)
+{
+       struct fsf_qual_latency_info *lat_inf;
+       struct latency_cont *lat;
+       struct zfcp_unit *unit;
+       unsigned long flags;
+
+       lat_inf = &fsf_req->qtcb->prefix.prot_status_qual.latency_info;
+       unit = fsf_req->unit;
+
+       switch (fsf_req->qtcb->bottom.io.data_direction) {
+       case FSF_DATADIR_READ:
+               lat = &unit->latencies.read;
+               break;
+       case FSF_DATADIR_WRITE:
+               lat = &unit->latencies.write;
+               break;
+       case FSF_DATADIR_CMND:
+               lat = &unit->latencies.cmd;
+               break;
+       default:
+               return;
+       }
+
+       spin_lock_irqsave(&unit->latencies.lock, flags);
+       zfcp_fsf_update_lat(&lat->channel, lat_inf->channel_lat);
+       zfcp_fsf_update_lat(&lat->fabric, lat_inf->fabric_lat);
+       lat->counter++;
+       spin_unlock_irqrestore(&unit->latencies.lock, flags);
+}
+
 /*
  * function:    zfcp_fsf_send_fcp_command_handler
  *
@@ -3922,6 +3963,9 @@ zfcp_fsf_send_fcp_command_task_handler(struct zfcp_fsf_req *fsf_req)
                              fcp_rsp_iu->fcp_sns_len);
        }
 
+       if (fsf_req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA)
+               zfcp_fsf_req_latency(fsf_req);
+
        /* check FCP_RSP_INFO */
        if (unlikely(fcp_rsp_iu->validity.bits.fcp_rsp_len_valid)) {
                ZFCP_LOG_DEBUG("rsp_len is valid\n");

diff --git a/drivers/s390/scsi/zfcp_fsf.h b/drivers/s390/scsi/zfcp_fsf.h
index 099970b2700175f01bbbad8de08e96871f108a7e..8b1a7d9c840fbff07e131d1066e6d58d33ae2d7f 100644 (file)
--- a/drivers/s390/scsi/zfcp_fsf.h
+++ b/drivers/s390/scsi/zfcp_fsf.h
@@ -323,11 +323,18 @@ struct fsf_link_down_info {
        u8 vendor_specific_code;
 } __attribute__ ((packed));
 
+struct fsf_qual_latency_info {
+       u32 channel_lat;
+       u32 fabric_lat;
+       u8 res1[8];
+} __attribute__ ((packed));
+
 union fsf_prot_status_qual {
        u64 doubleword[FSF_PROT_STATUS_QUAL_SIZE / sizeof(u64)];
        struct fsf_qual_version_error   version_error;
        struct fsf_qual_sequence_error  sequence_error;
        struct fsf_link_down_info link_down_info;
+       struct fsf_qual_latency_info latency_info;
 } __attribute__ ((packed));
 
 struct fsf_qtcb_prefix {
@@ -437,7 +444,9 @@ struct fsf_qtcb_bottom_config {
        u32 fc_link_speed;
        u32 adapter_type;
        u32 peer_d_id;
-       u8 res2[12];
+       u8 res1[2];
+       u16 timer_interval;
+       u8 res2[8];
        u32 s_id;
        struct fsf_nport_serv_param nport_serv_param;
        u8 reserved_nport_serv_param[16];