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vdev_queue: per-vdev stats
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Adding a bunch of gauges and counters to show in-flight and total IOs,
with per-class breakdowns, and some aggregation counters.

Sponsored-by: Klara, Inc.
Sponsored-by: Syneto
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
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@robn
robn committed May 21, 2024
1 parent b827625 commit 0a9a614
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Showing 2 changed files with 264 additions and 5 deletions.
25 changes: 24 additions & 1 deletion include/sys/vdev_impl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,8 @@
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011, 2020 by Delphix. All rights reserved.
* Copyright (c) 2017, Intel Corporation.
* Copyright (c) 2023, Klara Inc.
* Copyright (c) 2023, 2024, Klara, Inc.
* Copyright (c) 2024, Syneto
*/

#ifndef _SYS_VDEV_IMPL_H
Expand All @@ -41,6 +42,7 @@
#include <sys/vdev_rebuild.h>
#include <sys/vdev_removal.h>
#include <sys/zfs_ratelimit.h>
#include <sys/wmsum.h>

#ifdef __cplusplus
extern "C" {
Expand Down Expand Up @@ -138,6 +140,25 @@ typedef union vdev_queue_class {
avl_tree_t vqc_tree;
} vdev_queue_class_t;

typedef struct vdev_queue_sums {
/* gauges (inc/dec counters, current value) */
wmsum_t vqs_io_queued;
wmsum_t vqs_io_class_queued[ZIO_PRIORITY_NUM_QUEUEABLE];
wmsum_t vqs_io_active;
wmsum_t vqs_io_class_active[ZIO_PRIORITY_NUM_QUEUEABLE];

/* counters (inc only, since queue creation ) */
wmsum_t vqs_io_enqueued_total;
wmsum_t vqs_io_class_enqueued_total[ZIO_PRIORITY_NUM_QUEUEABLE];
wmsum_t vqs_io_dequeued_total;
wmsum_t vqs_io_class_dequeued_total[ZIO_PRIORITY_NUM_QUEUEABLE];
wmsum_t vqs_io_aggregated_total;
wmsum_t vqs_io_aggregated_data_total;
wmsum_t vqs_io_aggregated_read_gap_total;
wmsum_t vqs_io_aggregated_write_gap_total;
wmsum_t vqs_io_aggregated_shrunk_total;
} vdev_queue_sums_t;

struct vdev_queue {
vdev_t *vq_vdev;
vdev_queue_class_t vq_class[ZIO_PRIORITY_NUM_QUEUEABLE];
Expand All @@ -155,6 +176,8 @@ struct vdev_queue {
hrtime_t vq_io_delta_ts;
zio_t vq_io_search; /* used as local for stack reduction */
kmutex_t vq_lock;
vdev_queue_sums_t vq_sums;
kstat_t *vq_ksp;
};

typedef enum vdev_alloc_bias {
Expand Down
244 changes: 240 additions & 4 deletions module/zfs/vdev_queue.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@

/*
* Copyright (c) 2012, 2018 by Delphix. All rights reserved.
* Copyright (c) 2024, Klara, Inc.
* Copyright (c) 2024, Syneto
*/

#include <sys/zfs_context.h>
Expand Down Expand Up @@ -228,6 +230,81 @@ uint_t zfs_vdev_queue_depth_pct = 300;
*/
uint_t zfs_vdev_def_queue_depth = 32;

typedef struct vdev_queue_kstats {
kstat_named_t vqks_io_queued;
kstat_named_t vqks_io_class_queued[ZIO_PRIORITY_NUM_QUEUEABLE];
kstat_named_t vqks_io_active;
kstat_named_t vqks_io_class_active[ZIO_PRIORITY_NUM_QUEUEABLE];
kstat_named_t vqks_io_enqueued_total;
kstat_named_t vqks_io_class_enqueued_total[ZIO_PRIORITY_NUM_QUEUEABLE];
kstat_named_t vqks_io_dequeued_total;
kstat_named_t vqks_io_class_dequeued_total[ZIO_PRIORITY_NUM_QUEUEABLE];
kstat_named_t vqks_io_aggregated_total;
kstat_named_t vqks_io_aggregated_data_total;
kstat_named_t vqks_io_aggregated_read_gap_total;
kstat_named_t vqks_io_aggregated_write_gap_total;
kstat_named_t vqks_io_aggregated_shrunk_total;
} vdev_queue_kstats_t;

static vdev_queue_kstats_t vdev_queue_kstats_template = {
{ "io_queued", KSTAT_DATA_UINT64 },
{
{ "io_syncread_queued", KSTAT_DATA_UINT64 },
{ "io_syncwrite_queued", KSTAT_DATA_UINT64 },
{ "io_asyncread_queued", KSTAT_DATA_UINT64 },
{ "io_asyncwrite_queued", KSTAT_DATA_UINT64 },
{ "io_scrub_queued", KSTAT_DATA_UINT64 },
{ "io_removal_queued", KSTAT_DATA_UINT64 },
{ "io_initializing_queued", KSTAT_DATA_UINT64 },
{ "io_trim_queued", KSTAT_DATA_UINT64 },
{ "io_rebuild_queued", KSTAT_DATA_UINT64 },
},
{ "io_active", KSTAT_DATA_UINT64 },
{
{ "io_syncread_active", KSTAT_DATA_UINT64 },
{ "io_syncwrite_active", KSTAT_DATA_UINT64 },
{ "io_asyncread_active", KSTAT_DATA_UINT64 },
{ "io_asyncwrite_active", KSTAT_DATA_UINT64 },
{ "io_scrub_active", KSTAT_DATA_UINT64 },
{ "io_removal_active", KSTAT_DATA_UINT64 },
{ "io_initializing_active", KSTAT_DATA_UINT64 },
{ "io_trim_active", KSTAT_DATA_UINT64 },
{ "io_rebuild_active", KSTAT_DATA_UINT64 },
},
{ "io_enqueued_total", KSTAT_DATA_UINT64 },
{
{ "io_syncread_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_syncwrite_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_asyncread_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_asyncwrite_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_scrub_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_removal_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_initializing_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_trim_enqueued_total", KSTAT_DATA_UINT64 },
{ "io_rebuild_enqueued_total", KSTAT_DATA_UINT64 },
},
{ "io_dequeued_total", KSTAT_DATA_UINT64 },
{
{ "io_syncread_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_syncwrite_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_asyncread_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_asyncwrite_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_scrub_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_removal_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_initializing_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_trim_dequeued_total", KSTAT_DATA_UINT64 },
{ "io_rebuild_dequeued_total", KSTAT_DATA_UINT64 },
},
{ "io_aggregated_total", KSTAT_DATA_UINT64 },
{ "io_aggregated_data_total", KSTAT_DATA_UINT64 },
{ "io_aggregated_read_gap_total", KSTAT_DATA_UINT64 },
{ "io_aggregated_write_gap_total", KSTAT_DATA_UINT64 },
{ "io_aggregated_shrunk_total", KSTAT_DATA_UINT64 },
};

#define VQSTAT_INC(vq, stat) wmsum_add(&vq->vq_sums.vqs_##stat, 1)
#define VQSTAT_DEC(vq, stat) wmsum_add(&vq->vq_sums.vqs_##stat, -1)

static int
vdev_queue_offset_compare(const void *x1, const void *x2)
{
Expand Down Expand Up @@ -279,6 +356,10 @@ vdev_queue_class_add(vdev_queue_t *vq, zio_t *zio)
}
else
avl_add(&vq->vq_class[p].vqc_tree, zio);
VQSTAT_INC(vq, io_queued);
VQSTAT_INC(vq, io_class_queued[p]);
VQSTAT_INC(vq, io_enqueued_total);
VQSTAT_INC(vq, io_class_enqueued_total[p]);
}

static void
Expand All @@ -297,6 +378,10 @@ vdev_queue_class_remove(vdev_queue_t *vq, zio_t *zio)
empty = avl_is_empty(tree);
}
vq->vq_cqueued &= ~(empty << p);
VQSTAT_DEC(vq, io_queued);
VQSTAT_DEC(vq, io_class_queued[p]);
VQSTAT_INC(vq, io_dequeued_total);
VQSTAT_INC(vq, io_class_dequeued_total[p]);
}

static uint_t
Expand Down Expand Up @@ -472,6 +557,129 @@ vdev_queue_class_to_issue(vdev_queue_t *vq)
return (p);
}

static void
vdev_queue_sums_init(vdev_queue_t *vq)
{
vdev_queue_sums_t *vqs = &vq->vq_sums;
wmsum_init(&vqs->vqs_io_queued, 0);
wmsum_init(&vqs->vqs_io_active, 0);
wmsum_init(&vqs->vqs_io_enqueued_total, 0);
wmsum_init(&vqs->vqs_io_dequeued_total, 0);
wmsum_init(&vqs->vqs_io_aggregated_total, 0);
wmsum_init(&vqs->vqs_io_aggregated_data_total, 0);
wmsum_init(&vqs->vqs_io_aggregated_read_gap_total, 0);
wmsum_init(&vqs->vqs_io_aggregated_write_gap_total, 0);
wmsum_init(&vqs->vqs_io_aggregated_shrunk_total, 0);
for (int i = 0; i < ZIO_PRIORITY_NUM_QUEUEABLE; i++) {
wmsum_init(&vqs->vqs_io_class_queued[i], 0);
wmsum_init(&vqs->vqs_io_class_active[i], 0);
wmsum_init(&vqs->vqs_io_class_enqueued_total[i], 0);
wmsum_init(&vqs->vqs_io_class_dequeued_total[i], 0);
}
}

static void
vdev_queue_sums_fini(vdev_queue_t *vq)
{
vdev_queue_sums_t *vqs = &vq->vq_sums;
wmsum_fini(&vqs->vqs_io_queued);
wmsum_fini(&vqs->vqs_io_active);
wmsum_fini(&vqs->vqs_io_enqueued_total);
wmsum_fini(&vqs->vqs_io_dequeued_total);
wmsum_fini(&vqs->vqs_io_aggregated_total);
wmsum_fini(&vqs->vqs_io_aggregated_data_total);
wmsum_fini(&vqs->vqs_io_aggregated_read_gap_total);
wmsum_fini(&vqs->vqs_io_aggregated_write_gap_total);
wmsum_fini(&vqs->vqs_io_aggregated_shrunk_total);
for (int i = 0; i < ZIO_PRIORITY_NUM_QUEUEABLE; i++) {
wmsum_fini(&vqs->vqs_io_class_queued[i]);
wmsum_fini(&vqs->vqs_io_class_active[i]);
wmsum_fini(&vqs->vqs_io_class_enqueued_total[i]);
wmsum_fini(&vqs->vqs_io_class_dequeued_total[i]);
}
}

static int
vdev_queue_kstats_update(kstat_t *ksp, int rw)
{
if (rw == KSTAT_WRITE)
return (EACCES);

vdev_queue_t *vq = ksp->ks_private;
vdev_queue_kstats_t *vqks = ksp->ks_data;
vdev_queue_sums_t *vqs = &vq->vq_sums;

vqks->vqks_io_queued.value.ui64 =
wmsum_value(&vqs->vqs_io_queued);
vqks->vqks_io_active.value.ui64 =
wmsum_value(&vqs->vqs_io_active);
vqks->vqks_io_enqueued_total.value.ui64 =
wmsum_value(&vqs->vqs_io_enqueued_total);
vqks->vqks_io_dequeued_total.value.ui64 =
wmsum_value(&vqs->vqs_io_dequeued_total);
vqks->vqks_io_aggregated_total.value.ui64 =
wmsum_value(&vqs->vqs_io_aggregated_total);
vqks->vqks_io_aggregated_data_total.value.ui64 =
wmsum_value(&vqs->vqs_io_aggregated_data_total);
vqks->vqks_io_aggregated_read_gap_total.value.ui64 =
wmsum_value(&vqs->vqs_io_aggregated_read_gap_total);
vqks->vqks_io_aggregated_write_gap_total.value.ui64 =
wmsum_value(&vqs->vqs_io_aggregated_write_gap_total);
vqks->vqks_io_aggregated_shrunk_total.value.ui64 =
wmsum_value(&vqs->vqs_io_aggregated_shrunk_total);
for (int i = 0; i < ZIO_PRIORITY_NUM_QUEUEABLE; i++) {
vqks->vqks_io_class_queued[i].value.ui64 =
wmsum_value(&vqs->vqs_io_class_queued[i]);
vqks->vqks_io_class_active[i].value.ui64 =
wmsum_value(&vqs->vqs_io_class_active[i]);
vqks->vqks_io_class_enqueued_total[i].value.ui64 =
wmsum_value(&vqs->vqs_io_class_enqueued_total[i]);
vqks->vqks_io_class_dequeued_total[i].value.ui64 =
wmsum_value(&vqs->vqs_io_class_dequeued_total[i]);
}

return (0);
}

static void
vdev_queue_kstats_init(vdev_queue_t *vq)
{
char *module =
kmem_asprintf("zfs/%s/vdev/%llu", spa_name(vq->vq_vdev->vdev_spa),
(u_longlong_t)vq->vq_vdev->vdev_guid);

kstat_t *ksp = kstat_create(module, 0, "queue", "misc",
KSTAT_TYPE_NAMED,
sizeof (vdev_queue_kstats_t) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);

kmem_strfree(module);

if (ksp == NULL)
return;

ksp->ks_private = vq;
ksp->ks_update = vdev_queue_kstats_update;
ksp->ks_data = kmem_alloc(sizeof (vdev_queue_kstats_t), KM_SLEEP);
memcpy(ksp->ks_data, &vdev_queue_kstats_template,
sizeof (vdev_queue_kstats_t));
kstat_install(ksp);

vq->vq_ksp = ksp;
}

static void
vdev_queue_kstats_fini(vdev_queue_t *vq)
{
if (vq->vq_ksp == NULL)
return;

kmem_free(vq->vq_ksp->ks_data, sizeof (vdev_queue_kstats_t));
kstat_delete(vq->vq_ksp);

vq->vq_ksp = NULL;
}

void
vdev_queue_init(vdev_t *vd)
{
Expand Down Expand Up @@ -502,13 +710,29 @@ vdev_queue_init(vdev_t *vd)
list_create(&vq->vq_active_list, sizeof (struct zio),
offsetof(struct zio, io_queue_node.l));
mutex_init(&vq->vq_lock, NULL, MUTEX_DEFAULT, NULL);

vdev_queue_sums_init(vq);

/*
* IO for interior vdevs and distributed spares never go through the
* queue, so do not create kstat nodes for them.
* See zio_vdev_io_start().
*/
if (spa_load_state(vd->vdev_spa) != SPA_LOAD_TRYIMPORT &&
vd->vdev_ops->vdev_op_leaf &&
vd->vdev_ops != &vdev_draid_spare_ops) {
vdev_queue_kstats_init(vq);
}
}

void
vdev_queue_fini(vdev_t *vd)
{
vdev_queue_t *vq = &vd->vdev_queue;

vdev_queue_kstats_fini(vq);
vdev_queue_sums_fini(vq);

for (zio_priority_t p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) {
if (vdev_queue_class_fifo(p))
list_destroy(&vq->vq_class[p].vqc_list);
Expand Down Expand Up @@ -563,9 +787,12 @@ vdev_queue_pending_add(vdev_queue_t *vq, zio_t *zio)
{
ASSERT(MUTEX_HELD(&vq->vq_lock));
ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
vq->vq_cactive[zio->io_priority]++;
zio_priority_t p = zio->io_priority;
vq->vq_cactive[p]++;
vq->vq_active++;
if (vdev_queue_is_interactive(zio->io_priority)) {
VQSTAT_INC(vq, io_active);
VQSTAT_INC(vq, io_class_active[p]);
if (vdev_queue_is_interactive(p)) {
if (++vq->vq_ia_active == 1)
vq->vq_nia_credit = 1;
} else if (vq->vq_ia_active > 0) {
Expand All @@ -580,9 +807,12 @@ vdev_queue_pending_remove(vdev_queue_t *vq, zio_t *zio)
{
ASSERT(MUTEX_HELD(&vq->vq_lock));
ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
vq->vq_cactive[zio->io_priority]--;
zio_priority_t p = zio->io_priority;
vq->vq_cactive[p]--;
vq->vq_active--;
if (vdev_queue_is_interactive(zio->io_priority)) {
VQSTAT_DEC(vq, io_active);
VQSTAT_DEC(vq, io_class_active[p]);
if (vdev_queue_is_interactive(p)) {
if (--vq->vq_ia_active == 0)
vq->vq_nia_credit = 0;
else
Expand Down Expand Up @@ -777,6 +1007,8 @@ vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
flags | ZIO_FLAG_DONT_QUEUE, vdev_queue_agg_io_done, NULL);
aio->io_timestamp = first->io_timestamp;

VQSTAT_INC(vq, io_aggregated_total);

nio = first;
next_offset = first->io_offset;
do {
Expand All @@ -785,6 +1017,7 @@ vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
ASSERT3P(dio, !=, NULL);
zio_add_child(dio, aio);
vdev_queue_io_remove(vq, dio);
VQSTAT_INC(vq, io_aggregated_data_total);

if (dio->io_offset != next_offset) {
/* allocate a buffer for a read gap */
Expand All @@ -793,20 +1026,23 @@ vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
abd = abd_alloc_for_io(
dio->io_offset - next_offset, B_TRUE);
abd_gang_add(aio->io_abd, abd, B_TRUE);
VQSTAT_INC(vq, io_aggregated_read_gap_total);
}
if (dio->io_abd &&
(dio->io_size != abd_get_size(dio->io_abd))) {
/* abd size not the same as IO size */
ASSERT3U(abd_get_size(dio->io_abd), >, dio->io_size);
abd = abd_get_offset_size(dio->io_abd, 0, dio->io_size);
abd_gang_add(aio->io_abd, abd, B_TRUE);
VQSTAT_INC(vq, io_aggregated_shrunk_total);
} else {
if (dio->io_flags & ZIO_FLAG_NODATA) {
/* allocate a buffer for a write gap */
ASSERT3U(dio->io_type, ==, ZIO_TYPE_WRITE);
ASSERT3P(dio->io_abd, ==, NULL);
abd_gang_add(aio->io_abd,
abd_get_zeros(dio->io_size), B_TRUE);
VQSTAT_INC(vq, io_aggregated_write_gap_total);
} else {
/*
* We pass B_FALSE to abd_gang_add()
Expand Down

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