Commit 2ee95af0 authored by Daniel Verkamp's avatar Daniel Verkamp Committed by Jim Harris
Browse files

bdev: stop zeroing data in spdk_bdev_get_io_stat() 



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: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/412257


Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
parent 881cbb60

CHANGELOG.md

+7 −0
Original line number Diff line number Diff line
@@ -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

include/spdk/bdev.h

+1 −2
Original line number Diff line number Diff line
@@ -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().

lib/bdev/bdev.c

+8 −13
Original line number Diff line number Diff line
@@ -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