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bdev/qos: add the bandwidth rate limit control
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This patch is to add the core control policy for the
bandwidth rate limit (max bytes per second). Change
the existing functions for a common name and specially
handle the case when IOPS and bandwidth rate limiting
are both enabled.

Change-Id: I9f4565958d472559ef6d8bea52b1fe2a5f3c8969
Signed-off-by: GangCao <[email protected]>
Reviewed-on: https://review.gerrithub.io/413821
Tested-by: SPDK Automated Test System <[email protected]>
Reviewed-by: Daniel Verkamp <[email protected]>
Reviewed-by: Jim Harris <[email protected]>
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@Comphix @jimharris
Comphix authored and jimharris committed Jun 12, 2018
1 parent 8da7772 commit 7191c4b
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Showing 2 changed files with 80 additions and 17 deletions.
80 changes: 64 additions & 16 deletions lib/bdev/bdev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,7 @@ int __itt_init_ittlib(const char *, __itt_group_id);
#define SPDK_BDEV_QOS_TIMESLICE_IN_USEC 1000
#define SPDK_BDEV_SEC_TO_USEC 1000000ULL
#define SPDK_BDEV_QOS_MIN_IO_PER_TIMESLICE 1
#define SPDK_BDEV_QOS_MIN_BYTE_PER_TIMESLICE 512
#define SPDK_BDEV_QOS_MIN_IOS_PER_SEC 10000
#define SPDK_BDEV_QOS_MIN_BW_IN_MB_PER_SEC 10

Expand Down Expand Up @@ -130,9 +131,16 @@ struct spdk_bdev_qos {
* only valid for the master channel which manages the outstanding IOs. */
uint64_t max_ios_per_timeslice;

/** Maximum allowed bytes to be issued in one timeslice (e.g., 1ms) and
* only valid for the master channel which manages the outstanding IOs. */
uint64_t max_byte_per_timeslice;

/** Submitted IO in one timeslice (e.g., 1ms) */
uint64_t io_submitted_this_timeslice;

/** Submitted byte in one timeslice (e.g., 1ms) */
uint64_t byte_submitted_this_timeslice;

/** Polller that processes queued I/O commands each time slice. */
struct spdk_poller *poller;
};
Expand Down Expand Up @@ -862,6 +870,26 @@ spdk_bdev_put_io(struct spdk_bdev_io *bdev_io)
}
}

static uint64_t
_spdk_bdev_get_io_size_in_byte(struct spdk_bdev_io *bdev_io)
{
struct spdk_bdev *bdev = bdev_io->bdev;

switch (bdev_io->type) {
case SPDK_BDEV_IO_TYPE_NVME_ADMIN:
case SPDK_BDEV_IO_TYPE_NVME_IO:
case SPDK_BDEV_IO_TYPE_NVME_IO_MD:
return bdev_io->u.nvme_passthru.nbytes;
case SPDK_BDEV_IO_TYPE_READ:
case SPDK_BDEV_IO_TYPE_WRITE:
case SPDK_BDEV_IO_TYPE_UNMAP:
case SPDK_BDEV_IO_TYPE_WRITE_ZEROES:
return bdev_io->u.bdev.num_blocks * bdev->blocklen;
default:
return 0;
}
}

static void
_spdk_bdev_qos_io_submit(struct spdk_bdev_channel *ch)
{
Expand All @@ -871,16 +899,23 @@ _spdk_bdev_qos_io_submit(struct spdk_bdev_channel *ch)
struct spdk_bdev_shared_resource *shared_resource = ch->shared_resource;

while (!TAILQ_EMPTY(&qos->queued)) {
if (qos->io_submitted_this_timeslice < qos->max_ios_per_timeslice) {
bdev_io = TAILQ_FIRST(&qos->queued);
TAILQ_REMOVE(&qos->queued, bdev_io, link);
qos->io_submitted_this_timeslice++;
ch->io_outstanding++;
shared_resource->io_outstanding++;
bdev->fn_table->submit_request(ch->channel, bdev_io);
} else {
if (qos->max_ios_per_timeslice > 0 &&
qos->io_submitted_this_timeslice >= qos->max_ios_per_timeslice) {
break;
}

if (qos->max_byte_per_timeslice > 0 &&
qos->byte_submitted_this_timeslice >= qos->max_byte_per_timeslice) {
break;
}

bdev_io = TAILQ_FIRST(&qos->queued);
TAILQ_REMOVE(&qos->queued, bdev_io, link);
qos->io_submitted_this_timeslice++;
qos->byte_submitted_this_timeslice += _spdk_bdev_get_io_size_in_byte(bdev_io);
ch->io_outstanding++;
shared_resource->io_outstanding++;
bdev->fn_table->submit_request(ch->channel, bdev_io);
}
}

Expand Down Expand Up @@ -1000,14 +1035,23 @@ spdk_bdev_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w)
}

static void
spdk_bdev_qos_update_max_ios_per_timeslice(struct spdk_bdev_qos *qos)
spdk_bdev_qos_update_max_quota_per_timeslice(struct spdk_bdev_qos *qos)
{
uint64_t max_ios_per_timeslice = 0;
uint64_t max_ios_per_timeslice = 0, max_byte_per_timeslice = 0;

max_ios_per_timeslice = qos->iops_rate_limit * SPDK_BDEV_QOS_TIMESLICE_IN_USEC /
SPDK_BDEV_SEC_TO_USEC;
qos->max_ios_per_timeslice = spdk_max(max_ios_per_timeslice,
SPDK_BDEV_QOS_MIN_IO_PER_TIMESLICE);
if (qos->iops_rate_limit > 0) {
max_ios_per_timeslice = qos->iops_rate_limit * SPDK_BDEV_QOS_TIMESLICE_IN_USEC /
SPDK_BDEV_SEC_TO_USEC;
qos->max_ios_per_timeslice = spdk_max(max_ios_per_timeslice,
SPDK_BDEV_QOS_MIN_IO_PER_TIMESLICE);
}

if (qos->byte_rate_limit > 0) {
max_byte_per_timeslice = qos->byte_rate_limit * SPDK_BDEV_QOS_TIMESLICE_IN_USEC /
SPDK_BDEV_SEC_TO_USEC;
qos->max_byte_per_timeslice = spdk_max(max_byte_per_timeslice,
SPDK_BDEV_QOS_MIN_BYTE_PER_TIMESLICE);
}
}

static int
Expand All @@ -1017,6 +1061,7 @@ spdk_bdev_channel_poll_qos(void *arg)

/* Reset for next round of rate limiting */
qos->io_submitted_this_timeslice = 0;
qos->byte_submitted_this_timeslice = 0;

_spdk_bdev_qos_io_submit(qos->ch);

Expand Down Expand Up @@ -1075,8 +1120,9 @@ _spdk_bdev_enable_qos(struct spdk_bdev *bdev, struct spdk_bdev_channel *ch)
qos->thread = spdk_io_channel_get_thread(io_ch);

TAILQ_INIT(&qos->queued);
spdk_bdev_qos_update_max_ios_per_timeslice(qos);
spdk_bdev_qos_update_max_quota_per_timeslice(qos);
qos->io_submitted_this_timeslice = 0;
qos->byte_submitted_this_timeslice = 0;

qos->poller = spdk_poller_register(spdk_bdev_channel_poll_qos,
qos,
Expand Down Expand Up @@ -1266,7 +1312,9 @@ spdk_bdev_qos_destroy(struct spdk_bdev *bdev)
new_qos->ch = NULL;
new_qos->thread = NULL;
new_qos->max_ios_per_timeslice = 0;
new_qos->max_byte_per_timeslice = 0;
new_qos->io_submitted_this_timeslice = 0;
new_qos->byte_submitted_this_timeslice = 0;
new_qos->poller = NULL;
TAILQ_INIT(&new_qos->queued);

Expand Down Expand Up @@ -3077,7 +3125,7 @@ _spdk_bdev_update_qos_limit_iops_msg(void *cb_arg)
struct spdk_bdev *bdev = ctx->bdev;

pthread_mutex_lock(&bdev->mutex);
spdk_bdev_qos_update_max_ios_per_timeslice(bdev->qos);
spdk_bdev_qos_update_max_quota_per_timeslice(bdev->qos);
pthread_mutex_unlock(&bdev->mutex);

_spdk_bdev_set_qos_limit_done(ctx, 0);
Expand Down
17 changes: 16 additions & 1 deletion test/unit/lib/bdev/mt/bdev.c/bdev_ut.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -629,7 +629,12 @@ basic_qos(void)
bdev->qos = calloc(1, sizeof(*bdev->qos));
SPDK_CU_ASSERT_FATAL(bdev->qos != NULL);
TAILQ_INIT(&bdev->qos->queued);
/*
* Enable both IOPS and bandwidth rate limits.
* In this case, both rate limits will take equal effect.
*/
bdev->qos->iops_rate_limit = 2000; /* 2 I/O per millisecond */
bdev->qos->byte_rate_limit = 8192000; /* 8K byte per millisecond with 4K block size */

g_get_io_channel = true;

Expand Down Expand Up @@ -732,7 +737,12 @@ io_during_qos_queue(void)
bdev->qos = calloc(1, sizeof(*bdev->qos));
SPDK_CU_ASSERT_FATAL(bdev->qos != NULL);
TAILQ_INIT(&bdev->qos->queued);
/*
* Enable both IOPS and bandwidth rate limits.
* In this case, IOPS rate limit will take effect first.
*/
bdev->qos->iops_rate_limit = 1000; /* 1000 I/O per second, or 1 per millisecond */
bdev->qos->byte_rate_limit = 8192000; /* 8K byte per millisecond with 4K block size */

g_get_io_channel = true;

Expand Down Expand Up @@ -815,7 +825,12 @@ io_during_qos_reset(void)
bdev->qos = calloc(1, sizeof(*bdev->qos));
SPDK_CU_ASSERT_FATAL(bdev->qos != NULL);
TAILQ_INIT(&bdev->qos->queued);
bdev->qos->iops_rate_limit = 1000; /* 1000 I/O per second, or 1 per millisecond */
/*
* Enable both IOPS and bandwidth rate limits.
* In this case, bandwidth rate limit will take effect first.
*/
bdev->qos->iops_rate_limit = 2000; /* 2000 I/O per second, or 2 per millisecond */
bdev->qos->byte_rate_limit = 4096000; /* 4K byte per millisecond with 4K block size */

g_get_io_channel = true;

Expand Down

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