In case I missed, is it possible to include iostat patch corresponding
to this kernel patch ?
On 6/3/19 6:29 PM, Xiaoguang Wang wrote:
> Indeed tool iostat's await is not good enough, which is somewhat sketchy
> and could not show request's latency on device driver's side.
>
> Here we add a new counter to track io request's d2c time, also with this
> patch, we can extend iostat to show this value easily.
>
> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
> ---
> block/blk-core.c | 3 +++
> block/genhd.c | 7 +++++--
> block/partition-generic.c | 8 ++++++--
> include/linux/genhd.h | 4 ++++
> 4 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index ee1b35fe8572..b0449ec80a7d 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1257,6 +1257,9 @@ void blk_account_io_done(struct request *req, u64 now)
> update_io_ticks(part, jiffies);
> part_stat_inc(part, ios[sgrp]);
> part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
> + if (req->io_start_time_ns)
> + part_stat_add(part, d2c_nsecs[sgrp],
> + now - req->io_start_time_ns);
> part_stat_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns));
> part_dec_in_flight(req->q, part, rq_data_dir(req));
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 24654e1d83e6..727bc1de1a74 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -1377,7 +1377,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
> "%lu %lu %lu %u "
> "%lu %lu %lu %u "
> "%u %u %u "
> - "%lu %lu %lu %u\n",
> + "%lu %lu %lu %u %u %u %u\n",
> MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
> disk_name(gp, hd->partno, buf),
> part_stat_read(hd, ios[STAT_READ]),
> @@ -1394,7 +1394,10 @@ static int diskstats_show(struct seq_file *seqf, void *v)
> part_stat_read(hd, ios[STAT_DISCARD]),
> part_stat_read(hd, merges[STAT_DISCARD]),
> part_stat_read(hd, sectors[STAT_DISCARD]),
> - (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD)
> + (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD),
> + (unsigned int)part_stat_read_d2c_msecs(hd, STAT_READ),
> + (unsigned int)part_stat_read_d2c_msecs(hd, STAT_WRITE),
> + (unsigned int)part_stat_read_d2c_msecs(hd, STAT_DISCARD)
> );
> }
> disk_part_iter_exit(&piter);
> diff --git a/block/partition-generic.c b/block/partition-generic.c
> index aee643ce13d1..0635a46a31dd 100644
> --- a/block/partition-generic.c
> +++ b/block/partition-generic.c
> @@ -127,7 +127,7 @@ ssize_t part_stat_show(struct device *dev,
> "%8lu %8lu %8llu %8u "
> "%8lu %8lu %8llu %8u "
> "%8u %8u %8u "
> - "%8lu %8lu %8llu %8u"
> + "%8lu %8lu %8llu %8u %8u %8u %8u %8u"
> "\n",
> part_stat_read(p, ios[STAT_READ]),
> part_stat_read(p, merges[STAT_READ]),
> @@ -143,7 +143,11 @@ ssize_t part_stat_show(struct device *dev,
> part_stat_read(p, ios[STAT_DISCARD]),
> part_stat_read(p, merges[STAT_DISCARD]),
> (unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]),
> - (unsigned int)part_stat_read_msecs(p, STAT_DISCARD));
> + (unsigned int)part_stat_read_msecs(p, STAT_DISCARD),
> + (unsigned int)part_stat_read_msecs(p, STAT_DISCARD),
> + (unsigned int)part_stat_read_d2c_msecs(p, STAT_READ),
> + (unsigned int)part_stat_read_d2c_msecs(p, STAT_WRITE),
> + (unsigned int)part_stat_read_d2c_msecs(p, STAT_DISCARD));
> }
>
> ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
> diff --git a/include/linux/genhd.h b/include/linux/genhd.h
> index 8b5330dd5ac0..f80ba947cac2 100644
> --- a/include/linux/genhd.h
> +++ b/include/linux/genhd.h
> @@ -85,6 +85,7 @@ struct partition {
>
> struct disk_stats {
> u64 nsecs[NR_STAT_GROUPS];
> + u64 d2c_nsecs[NR_STAT_GROUPS];
> unsigned long sectors[NR_STAT_GROUPS];
> unsigned long ios[NR_STAT_GROUPS];
> unsigned long merges[NR_STAT_GROUPS];
> @@ -367,6 +368,9 @@ static inline void free_part_stats(struct hd_struct *part)
> #define part_stat_read_msecs(part, which) \
> div_u64(part_stat_read(part, nsecs[which]), NSEC_PER_MSEC)
>
> +#define part_stat_read_d2c_msecs(part, which) \
> + div_u64(part_stat_read(part, d2c_nsecs[which]), NSEC_PER_MSEC)
> +
> #define part_stat_read_accum(part, field) \
> (part_stat_read(part, field[STAT_READ]) + \
> part_stat_read(part, field[STAT_WRITE]) + \
>
