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authorSeymour, Shane M <shane.seymour@hp.com>2015-05-06 04:37:20 +0300
committerJames Bottomley <JBottomley@Odin.com>2015-06-02 18:03:25 +0300
commit05545c92db9637318a98d3d59d400beb819decc7 (patch)
tree56c911568dd7dd6507aac24f7c8c90b657f7bda0 /drivers/scsi/st.h
parentba929992522b6d1f866b7021bc50da66f8fdd743 (diff)
downloadlinux-05545c92db9637318a98d3d59d400beb819decc7.tar.xz
st: implement tape statistics
This patch implements tape statistics in the st module via sysfs. Current no statistics are available for tape I/O and there is no easy way to reuse the block layer statistics for tape as tape is a character device and does not have perform I/O in sector sized chunks (the size of the data written to tape can change). For tapes we also need extra stats related to things like tape movement (via other I/O). There have been multiple end users requesting statistics including AT&T (and some HP customers who have not given permission to be named). It is impossible for them to investigate any issues related to tape performance in a non-invasive way. [jejb: eliminate PRId64] Signed-off-by: Shane Seymour <shane.seymour@hp.com> Tested-by: Shane Seymour <shane.seymour@hp.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
Diffstat (limited to 'drivers/scsi/st.h')
-rw-r--r--drivers/scsi/st.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index f3eee0f9f40c..b6486b5d8681 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -92,6 +92,27 @@ struct st_partstat {
int drv_file;
};
+/* Tape statistics */
+struct scsi_tape_stats {
+ atomic64_t read_byte_cnt; /* bytes read */
+ atomic64_t write_byte_cnt; /* bytes written */
+ atomic64_t in_flight; /* Number of I/Os in flight */
+ atomic64_t read_cnt; /* Count of read requests */
+ atomic64_t write_cnt; /* Count of write requests */
+ atomic64_t other_cnt; /* Count of other requests either
+ * implicit or from user space
+ * ioctl. */
+ atomic64_t resid_cnt; /* Count of resid_len > 0 */
+ atomic64_t tot_read_time; /* ktime spent completing reads */
+ atomic64_t tot_write_time; /* ktime spent completing writes */
+ atomic64_t tot_io_time; /* ktime spent doing any I/O */
+ ktime_t read_time; /* holds ktime request was queued */
+ ktime_t write_time; /* holds ktime request was queued */
+ ktime_t other_time; /* holds ktime request was queued */
+ atomic_t last_read_size; /* Number of bytes issued for last read */
+ atomic_t last_write_size; /* Number of bytes issued for last write */
+};
+
#define ST_NBR_PARTITIONS 4
/* The tape drive descriptor */
@@ -171,6 +192,7 @@ struct scsi_tape {
#endif
struct gendisk *disk;
struct kref kref;
+ struct scsi_tape_stats *stats;
};
/* Bit masks for use_pf */