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bdev: stop zeroing data in spdk_bdev_get_io_stat()

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This will allow multiple independent callers to request I/O statistics
without stepping on each other (previously the stats would be reset on
each request, which only works with a single caller).

This also means that we can now allow requesting stats while the VTune
integration is enabled.

Change-Id: Ia9d4d6fd37fa66b3671cd33b3183c90524f955bd
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/412257
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
This commit is contained in:
Daniel Verkamp 2018-05-23 11:30:01 -07:00 committed by Jim Harris
parent 881cbb60a4
commit 2ee95af0fd
3 changed files with 16 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
CHANGELOG.md
View File

@ -2,6 +2,13 @@
## v18.07: (Upcoming Release)
### Bdev
The spdk_bdev_get_io_stat() function now returns cumulative totals instead of resetting
on each call. This allows multiple callers to query I/O statistics without conflicting
with each other. Existing users will need to adjust their code to record the previous
I/O statistics to calculate the delta between calls.
### git pre-commit and pre-push hooks
The pre-commit hook will run `scripts/check_format.sh` and verify there are no formating

3
include/spdk/bdev.h
View File

@ -776,8 +776,7 @@ int spdk_bdev_nvme_io_passthru_md(struct spdk_bdev_desc *bdev_desc,
int spdk_bdev_free_io(struct spdk_bdev_io *bdev_io);
/**
* Return I/O statistics for this channel. After returning stats, zero out
* the current state of the statistics.
* Return I/O statistics for this channel.
*
* \param bdev Block device.
* \param ch I/O channel. Obtained by calling spdk_bdev_get_io_channel().

21
lib/bdev/bdev.c
View File

@ -205,6 +205,7 @@ struct spdk_bdev_channel {
uint64_t start_tsc;
uint64_t interval_tsc;
__itt_string_handle *handle;
struct spdk_bdev_io_stat prev_stat;
#endif
};
@ -1117,6 +1118,7 @@ spdk_bdev_channel_create(void *io_device, void *ctx_buf)
}
memset(&ch->stat, 0, sizeof(ch->stat));
ch->stat.ticks_rate = spdk_get_ticks_hz();
ch->io_outstanding = 0;
TAILQ_INIT(&ch->queued_resets);
ch->flags = 0;
@ -1135,6 +1137,7 @@ spdk_bdev_channel_create(void *io_device, void *ctx_buf)
free(name);
ch->start_tsc = spdk_get_ticks();
ch->interval_tsc = spdk_get_ticks_hz() / 100;
memset(&ch->prev_stat, 0, sizeof(ch->prev_stat));
}
#endif
@ -1961,17 +1964,9 @@ void
spdk_bdev_get_io_stat(struct spdk_bdev *bdev, struct spdk_io_channel *ch,
struct spdk_bdev_io_stat *stat)
{
#ifdef SPDK_CONFIG_VTUNE
SPDK_ERRLOG("Calling spdk_bdev_get_io_stat is not allowed when VTune integration is enabled.\n");
memset(stat, 0, sizeof(*stat));
return;
#endif
struct spdk_bdev_channel *channel = spdk_io_channel_get_ctx(ch);
channel->stat.ticks_rate = spdk_get_ticks_hz();
*stat = channel->stat;
memset(&channel->stat, 0, sizeof(channel->stat));
}
static void
@ -2233,17 +2228,17 @@ _spdk_bdev_io_complete(void *ctx)
if (now_tsc > (bdev_io->ch->start_tsc + bdev_io->ch->interval_tsc)) {
uint64_t data[5];
data[0] = bdev_io->ch->stat.num_read_ops;
data[1] = bdev_io->ch->stat.bytes_read;
data[2] = bdev_io->ch->stat.num_write_ops;
data[3] = bdev_io->ch->stat.bytes_written;
data[0] = bdev_io->ch->stat.num_read_ops - bdev_io->ch->prev_stat.num_read_ops;
data[1] = bdev_io->ch->stat.bytes_read - bdev_io->ch->prev_stat.bytes_read;
data[2] = bdev_io->ch->stat.num_write_ops - bdev_io->ch->prev_stat.num_write_ops;
data[3] = bdev_io->ch->stat.bytes_written - bdev_io->ch->prev_stat.bytes_written;
data[4] = bdev_io->bdev->fn_table->get_spin_time ?
bdev_io->bdev->fn_table->get_spin_time(bdev_io->ch->channel) : 0;
__itt_metadata_add(g_bdev_mgr.domain, __itt_null, bdev_io->ch->handle,
__itt_metadata_u64, 5, data);
memset(&bdev_io->ch->stat, 0, sizeof(bdev_io->ch->stat));
bdev_io->ch->prev_stat = bdev_io->ch->stat;
bdev_io->ch->start_tsc = now_tsc;
}
#endif