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| author | Seymour, Shane M <shane.seymour@hp.com> | 2015-05-06 01:37:20 +0000 |
|---|---|---|
| committer | James Bottomley <JBottomley@Odin.com> | 2015-06-02 08:03:25 -0700 |
| commit | 05545c92db9637318a98d3d59d400beb819decc7 (patch) | |
| tree | 56c911568dd7dd6507aac24f7c8c90b657f7bda0 /drivers/scsi/st.h | |
| parent | ba929992522b6d1f866b7021bc50da66f8fdd743 (diff) | |
| download | lwn-05545c92db9637318a98d3d59d400beb819decc7.tar.gz lwn-05545c92db9637318a98d3d59d400beb819decc7.zip | |
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.h | 22 |
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 */ |