>From Leonid Ananiev
Fully modular io schedulers and enables online switching between
them was introduced in Linux 2.6.10 but as a result percentage of CPU
using by kernel was increased and performance degradation is marked on
Itanium. A cause of degradation is in more steps for indirect IO
scheduler type specific function calls.
The patch eliminates 45 indirect function calls in 16 elevator
functions. Sysbench fileio benchmark throughput was increased at 2% for
noop elevator after patching.
Signed-off-by: Leonid Ananiev [email protected]
---
diff -rup linux-2.6.14-rc2/drivers/block/as-iosched.c
linux-2.6.14-rc2elv1/drivers/block/as-iosched.c
--- linux-2.6.14-rc2/drivers/block/as-iosched.c 2005-09-24
09:13:54.000000000 +0400
+++ linux-2.6.14-rc2elv1/drivers/block/as-iosched.c 2005-10-13
04:18:12.000000000 +0400
@@ -614,7 +614,7 @@ static void as_antic_stop(struct as_data
static void as_antic_timeout(unsigned long data)
{
struct request_queue *q = (struct request_queue *)data;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
@@ -945,7 +945,7 @@ static void update_write_batch(struct as
*/
static void as_completed_request(request_queue_t *q, struct request
*rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);
WARN_ON(!list_empty(&rq->queuelist));
@@ -1030,7 +1030,7 @@ static void as_remove_queued_request(req
{
struct as_rq *arq = RQ_DATA(rq);
const int data_dir = arq->is_sync;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
WARN_ON(arq->state != AS_RQ_QUEUED);
@@ -1361,7 +1361,7 @@ fifo_expired:
static struct request *as_next_request(request_queue_t *q)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct request *rq = NULL;
/*
@@ -1465,7 +1465,7 @@ static void as_add_request(struct as_dat
static void as_deactivate_request(request_queue_t *q, struct request
*rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);
if (arq) {
@@ -1510,7 +1510,7 @@ static void as_account_queued_request(st
static void
as_insert_request(request_queue_t *q, struct request *rq, int where)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);
if (arq) {
@@ -1563,7 +1563,7 @@ as_insert_request(request_queue_t *q, st
*/
static int as_queue_empty(request_queue_t *q)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
if (!list_empty(&ad->fifo_list[REQ_ASYNC])
|| !list_empty(&ad->fifo_list[REQ_SYNC])
@@ -1602,7 +1602,7 @@ as_latter_request(request_queue_t *q, st
static int
as_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
sector_t rb_key = bio->bi_sector + bio_sectors(bio);
struct request *__rq;
int ret;
@@ -1657,7 +1657,7 @@ out_insert:
static void as_merged_request(request_queue_t *q, struct request *req)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(req);
/*
@@ -1702,7 +1702,7 @@ static void
as_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(req);
struct as_rq *anext = RQ_DATA(next);
@@ -1789,7 +1789,7 @@ static void as_work_handler(void *data)
static void as_put_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = RQ_DATA(rq);
if (!arq) {
@@ -1809,7 +1809,7 @@ static void as_put_request(request_queue
static int as_set_request(request_queue_t *q, struct request *rq,
struct bio *bio, int gfp_mask)
{
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct as_rq *arq = mempool_alloc(ad->arq_pool, gfp_mask);
if (arq) {
@@ -1831,7 +1831,7 @@ static int as_set_request(request_queue_
static int as_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
int ret = ELV_MQUEUE_MAY;
- struct as_data *ad = q->elevator->elevator_data;
+ struct as_data *ad = q->elevator.elevator_data;
struct io_context *ioc;
if (ad->antic_status == ANTIC_WAIT_REQ ||
ad->antic_status == ANTIC_WAIT_NEXT) {
diff -rup linux-2.6.14-rc2/drivers/block/cfq-iosched.c
linux-2.6.14-rc2elv1/drivers/block/cfq-iosched.c
--- linux-2.6.14-rc2/drivers/block/cfq-iosched.c 2005-09-24
09:13:54.000000000 +0400
+++ linux-2.6.14-rc2elv1/drivers/block/cfq-iosched.c 2005-10-13
04:18:12.000000000 +0400
@@ -364,7 +364,7 @@ static inline void cfq_schedule_dispatch
static int cfq_queue_empty(request_queue_t *q)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
return !cfq_pending_requests(cfqd);
}
@@ -678,7 +678,7 @@ out:
static void cfq_deactivate_request(request_queue_t *q, struct request
*rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
@@ -724,7 +724,7 @@ static void cfq_remove_request(request_q
static int
cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct request *__rq;
int ret;
@@ -756,7 +756,7 @@ out_insert:
static void cfq_merged_request(request_queue_t *q, struct request *req)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(req);
cfq_del_crq_hash(crq);
@@ -999,7 +999,7 @@ static int cfq_arm_slice_timer(struct cf
*/
static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_queue *cfqq = crq->cfq_queue;
struct list_head *head = &q->queue_head, *entry = head;
struct request *__rq;
@@ -1196,7 +1196,7 @@ __cfq_dispatch_requests(struct cfq_data
static int
cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_queue *cfqq;
if (!cfqd->busy_queues)
@@ -1270,7 +1270,7 @@ cfq_account_completion(struct cfq_queue
static struct request *cfq_next_request(request_queue_t *q)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct request *rq;
if (!list_empty(&q->queue_head)) {
@@ -1840,7 +1840,7 @@ static void cfq_enqueue(struct cfq_data
static void
cfq_insert_request(request_queue_t *q, struct request *rq, int where)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
switch (where) {
case ELEVATOR_INSERT_BACK:
@@ -2006,7 +2006,7 @@ __cfq_may_queue(struct cfq_data *cfqd, s
static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct task_struct *tsk = current;
struct cfq_queue *cfqq;
@@ -2029,7 +2029,7 @@ static int cfq_may_queue(request_queue_t
static void cfq_check_waiters(request_queue_t *q, struct cfq_queue
*cfqq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct request_list *rl = &q->rq;
if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved)
{
@@ -2050,7 +2050,7 @@ static void cfq_check_waiters(request_qu
*/
static void cfq_put_request(request_queue_t *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
@@ -2077,7 +2077,7 @@ static int
cfq_set_request(request_queue_t *q, struct request *rq, struct bio
*bio,
int gfp_mask)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
struct task_struct *tsk = current;
struct cfq_io_context *cic;
const int rw = rq_data_dir(rq);
@@ -2153,7 +2153,7 @@ queue_fail:
static void cfq_kick_queue(void *data)
{
request_queue_t *q = data;
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd = q->elevator.elevator_data;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
@@ -2263,7 +2263,7 @@ static void cfq_put_cfqd(struct cfq_data
blk_put_queue(q);
cfq_shutdown_timer_wq(cfqd);
- q->elevator->elevator_data = NULL;
+ q->elevator.elevator_data = NULL;
mempool_destroy(cfqd->crq_pool);
kfree(cfqd->crq_hash);
diff -rup linux-2.6.14-rc2/drivers/block/deadline-iosched.c
linux-2.6.14-rc2elv1/drivers/block/deadline-iosched.c
--- linux-2.6.14-rc2/drivers/block/deadline-iosched.c 2005-09-24
09:16:32.000000000 +0400
+++ linux-2.6.14-rc2elv1/drivers/block/deadline-iosched.c 2005-10-13
04:18:12.000000000 +0400
@@ -289,7 +289,7 @@ deadline_find_first_drq(struct deadline_
static inline void
deadline_add_request(struct request_queue *q, struct request *rq)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);
const int data_dir = rq_data_dir(drq->request);
@@ -317,7 +317,7 @@ static void deadline_remove_request(requ
struct deadline_rq *drq = RQ_DATA(rq);
if (drq) {
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
list_del_init(&drq->fifo);
deadline_remove_merge_hints(q, drq);
@@ -328,7 +328,7 @@ static void deadline_remove_request(requ
static int
deadline_merge(request_queue_t *q, struct request **req, struct bio
*bio)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct request *__rq;
int ret;
@@ -383,7 +383,7 @@ out_insert:
static void deadline_merged_request(request_queue_t *q, struct request
*req)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);
/*
@@ -407,7 +407,7 @@ static void
deadline_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(req);
struct deadline_rq *dnext = RQ_DATA(next);
@@ -599,7 +599,7 @@ dispatch_request:
static struct request *deadline_next_request(request_queue_t *q)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct request *rq;
/*
@@ -620,7 +620,7 @@ dispatch:
static void
deadline_insert_request(request_queue_t *q, struct request *rq, int
where)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
/* barriers must flush the reorder queue */
if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)
@@ -648,7 +648,7 @@ deadline_insert_request(request_queue_t
static int deadline_queue_empty(request_queue_t *q)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
if (!list_empty(&dd->fifo_list[WRITE])
|| !list_empty(&dd->fifo_list[READ])
@@ -745,7 +745,7 @@ static int deadline_init_queue(request_q
static void deadline_put_request(request_queue_t *q, struct request
*rq)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);
if (drq) {
@@ -758,7 +758,7 @@ static int
deadline_set_request(request_queue_t *q, struct request *rq, struct bio
*bio,
int gfp_mask)
{
- struct deadline_data *dd = q->elevator->elevator_data;
+ struct deadline_data *dd = q->elevator.elevator_data;
struct deadline_rq *drq;
drq = mempool_alloc(dd->drq_pool, gfp_mask);
diff -rup linux-2.6.14-rc2/drivers/block/elevator.c
linux-2.6.14-rc2elv1/drivers/block/elevator.c
--- linux-2.6.14-rc2/drivers/block/elevator.c 2005-09-24
09:13:54.000000000 +0400
+++ linux-2.6.14-rc2elv1/drivers/block/elevator.c 2005-10-13
04:18:12.000000000 +0400
@@ -130,18 +130,17 @@ static struct elevator_type *elevator_ge
return e;
}
-static int elevator_attach(request_queue_t *q, struct elevator_type *e,
- struct elevator_queue *eq)
+static int elevator_attach(request_queue_t *q, struct elevator_type *e)
{
int ret = 0;
+ struct elevator_queue *eq;
- memset(eq, 0, sizeof(*eq));
+ eq = &q->elevator;
eq->ops = &e->ops;
eq->elevator_type = e;
INIT_LIST_HEAD(&q->queue_head);
q->last_merge = NULL;
- q->elevator = eq;
if (eq->ops->elevator_init_fn)
ret = eq->ops->elevator_init_fn(q, eq);
@@ -183,7 +182,6 @@ __setup("elevator=", elevator_setup);
int elevator_init(request_queue_t *q, char *name)
{
struct elevator_type *e = NULL;
- struct elevator_queue *eq;
int ret = 0;
elevator_setup_default();
@@ -195,15 +193,8 @@ int elevator_init(request_queue_t *q, ch
if (!e)
return -EINVAL;
- eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
- if (!eq) {
- elevator_put(e->elevator_type);
- return -ENOMEM;
- }
-
- ret = elevator_attach(q, e, eq);
+ ret = elevator_attach(q, e);
if (ret) {
- kfree(eq);
elevator_put(e->elevator_type);
}
@@ -217,12 +208,11 @@ void elevator_exit(elevator_t *e)
elevator_put(e->elevator_type);
e->elevator_type = NULL;
- kfree(e);
}
int elv_merge(request_queue_t *q, struct request **req, struct bio
*bio)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_merge_fn)
return e->ops->elevator_merge_fn(q, req, bio);
@@ -232,7 +222,7 @@ int elv_merge(request_queue_t *q, struct
void elv_merged_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_merged_fn)
e->ops->elevator_merged_fn(q, rq);
@@ -241,7 +231,7 @@ void elv_merged_request(request_queue_t
void elv_merge_requests(request_queue_t *q, struct request *rq,
struct request *next)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (q->last_merge == next)
q->last_merge = NULL;
@@ -258,7 +248,7 @@ void elv_merge_requests(request_queue_t
*/
void elv_deactivate_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
/*
* it already went through dequeue, we need to decrement the
@@ -296,8 +286,8 @@ void elv_requeue_request(request_queue_t
* if iosched has an explicit requeue hook, then use that.
otherwise
* just put the request at the front of the queue
*/
- if (q->elevator->ops->elevator_requeue_req_fn)
- q->elevator->ops->elevator_requeue_req_fn(q, rq);
+ if (q->elevator.ops->elevator_requeue_req_fn)
+ q->elevator.ops->elevator_requeue_req_fn(q, rq);
else
__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0);
}
@@ -318,7 +308,7 @@ void __elv_add_request(request_queue_t *
rq->q = q;
if (!test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags)) {
- q->elevator->ops->elevator_add_req_fn(q, rq, where);
+ q->elevator.ops->elevator_add_req_fn(q, rq, where);
if (blk_queue_plugged(q)) {
int nrq = q->rq.count[READ] + q->rq.count[WRITE]
@@ -348,7 +338,7 @@ void elv_add_request(request_queue_t *q,
static inline struct request *__elv_next_request(request_queue_t *q)
{
- struct request *rq = q->elevator->ops->elevator_next_req_fn(q);
+ struct request *rq = q->elevator.ops->elevator_next_req_fn(q);
/*
* if this is a barrier write and the device has to issue a
@@ -418,7 +408,7 @@ struct request *elv_next_request(request
void elv_remove_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
/*
* the time frame between a request being removed from the lists
@@ -446,7 +436,7 @@ void elv_remove_request(request_queue_t
int elv_queue_empty(request_queue_t *q)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_queue_empty_fn)
return e->ops->elevator_queue_empty_fn(q);
@@ -458,7 +448,7 @@ struct request *elv_latter_request(reque
{
struct list_head *next;
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_latter_req_fn)
return e->ops->elevator_latter_req_fn(q, rq);
@@ -474,7 +464,7 @@ struct request *elv_former_request(reque
{
struct list_head *prev;
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_former_req_fn)
return e->ops->elevator_former_req_fn(q, rq);
@@ -489,7 +479,7 @@ struct request *elv_former_request(reque
int elv_set_request(request_queue_t *q, struct request *rq, struct bio
*bio,
int gfp_mask)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_set_req_fn)
return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
@@ -500,7 +490,7 @@ int elv_set_request(request_queue_t *q,
void elv_put_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_put_req_fn)
e->ops->elevator_put_req_fn(q, rq);
@@ -508,7 +498,7 @@ void elv_put_request(request_queue_t *q,
int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
if (e->ops->elevator_may_queue_fn)
return e->ops->elevator_may_queue_fn(q, rw, bio);
@@ -518,7 +508,7 @@ int elv_may_queue(request_queue_t *q, in
void elv_completed_request(request_queue_t *q, struct request *rq)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
/*
* request is released from the driver, io must be done
@@ -532,7 +522,7 @@ void elv_completed_request(request_queue
int elv_register_queue(struct request_queue *q)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
e->kobj.parent = kobject_get(&q->kobj);
if (!e->kobj.parent)
@@ -547,7 +537,7 @@ int elv_register_queue(struct request_qu
void elv_unregister_queue(struct request_queue *q)
{
if (q) {
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
kobject_unregister(&e->kobj);
kobject_put(&q->kobj);
}
@@ -590,12 +580,8 @@ EXPORT_SYMBOL_GPL(elv_unregister);
*/
static void elevator_switch(request_queue_t *q, struct elevator_type
*new_e)
{
- elevator_t *e = kmalloc(sizeof(elevator_t), GFP_KERNEL);
struct elevator_type *noop_elevator = NULL;
- elevator_t *old_elevator;
-
- if (!e)
- goto error;
+ elevator_t old_elevator;
/*
* first step, drain requests from the block freelist
@@ -615,7 +601,7 @@ static void elevator_switch(request_queu
*/
noop_elevator = elevator_get("noop");
spin_lock_irq(q->queue_lock);
- elevator_attach(q, noop_elevator, e);
+ elevator_attach(q, noop_elevator);
spin_unlock_irq(q->queue_lock);
blk_wait_queue_drained(q, 1);
@@ -623,7 +609,7 @@ static void elevator_switch(request_queu
/*
* attach and start new elevator
*/
- if (elevator_attach(q, new_e, e))
+ if (elevator_attach(q, new_e))
goto fail;
if (elv_register_queue(q))
@@ -632,7 +618,7 @@ static void elevator_switch(request_queu
/*
* finally exit old elevator and start queue again
*/
- elevator_exit(old_elevator);
+ elevator_exit(&old_elevator);
blk_finish_queue_drain(q);
elevator_put(noop_elevator);
return;
@@ -642,14 +628,12 @@ fail_register:
* switch failed, exit the new io scheduler and reattach the old
* one again (along with re-adding the sysfs dir)
*/
- elevator_exit(e);
+ elevator_exit(&q->elevator);
fail:
q->elevator = old_elevator;
elv_register_queue(q);
blk_finish_queue_drain(q);
-error:
- if (noop_elevator)
- elevator_put(noop_elevator);
+ elevator_put(noop_elevator);
elevator_put(new_e);
printk(KERN_ERR "elevator: switch to %s
failed\n",new_e->elevator_name);
}
@@ -671,7 +655,7 @@ ssize_t elv_iosched_store(request_queue_
return -EINVAL;
}
- if (!strcmp(elevator_name,
q->elevator->elevator_type->elevator_name))
+ if (!strcmp(elevator_name,
q->elevator.elevator_type->elevator_name))
return count;
elevator_switch(q, e);
@@ -680,7 +664,7 @@ ssize_t elv_iosched_store(request_queue_
ssize_t elv_iosched_show(request_queue_t *q, char *name)
{
- elevator_t *e = q->elevator;
+ elevator_t *e = &q->elevator;
struct elevator_type *elv = e->elevator_type;
struct list_head *entry;
int len = 0;
diff -rup linux-2.6.14-rc2/drivers/block/ll_rw_blk.c
linux-2.6.14-rc2elv1/drivers/block/ll_rw_blk.c
--- linux-2.6.14-rc2/drivers/block/ll_rw_blk.c 2005-09-24
09:16:32.000000000 +0400
+++ linux-2.6.14-rc2elv1/drivers/block/ll_rw_blk.c 2005-10-13
04:18:12.000000000 +0400
@@ -1613,8 +1613,7 @@ void blk_cleanup_queue(request_queue_t *
if (!atomic_dec_and_test(&q->refcnt))
return;
- if (q->elevator)
- elevator_exit(q->elevator);
+ elevator_exit(&q->elevator);
blk_sync_queue(q);
diff -rup linux-2.6.14-rc2/include/linux/blkdev.h
linux-2.6.14-rc2elv1/include/linux/blkdev.h
--- linux-2.6.14-rc2/include/linux/blkdev.h 2005-09-24
09:16:47.000000000 +0400
+++ linux-2.6.14-rc2elv1/include/linux/blkdev.h 2005-10-13
04:18:12.000000000 +0400
@@ -312,7 +312,7 @@ struct request_queue
*/
struct list_head queue_head;
struct request *last_merge;
- elevator_t *elevator;
+ elevator_t elevator;
/*
* the queue request freelist, one for reads and one for writes
On Thu, 13 Oct 2005, Ananiev, Leonid I wrote:
> >From Leonid Ananiev
>
> Fully modular io schedulers and enables online switching between
> them was introduced in Linux 2.6.10 but as a result percentage of CPU
> using by kernel was increased and performance degradation is marked on
> Itanium. A cause of degradation is in more steps for indirect IO
> scheduler type specific function calls.
> The patch eliminates 45 indirect function calls in 16 elevator
> functions. Sysbench fileio benchmark throughput was increased at 2% for
> noop elevator after patching.
>
> Signed-off-by: Leonid Ananiev [email protected]
Hi-
Put <...> around the email address.
> ---
patching file drivers/block/as-iosched.c
patch: **** malformed patch at line 39:
Ugh. Does exchange (server) add all of those extra lines?
> diff -rup linux-2.6.14-rc2/drivers/block/as-iosched.c
> linux-2.6.14-rc2elv1/drivers/block/as-iosched.c
>
> --- linux-2.6.14-rc2/drivers/block/as-iosched.c 2005-09-24
> 09:13:54.000000000 +0400
>
> +++ linux-2.6.14-rc2elv1/drivers/block/as-iosched.c 2005-10-13
> 04:18:12.000000000 +0400
>
> @@ -614,7 +614,7 @@ static void as_antic_stop(struct as_data
>
> static void as_antic_timeout(unsigned long data)
>
> {
>
> struct request_queue *q = (struct request_queue *)data;
>
> - struct as_data *ad = q->elevator->elevator_data;
>
> + struct as_data *ad = q->elevator.elevator_data;
>
> unsigned long flags;
>
>
>
> spin_lock_irqsave(q->queue_lock, flags);
--
~Randy
On Thu, Oct 13 2005, Ananiev, Leonid I wrote:
>
>
> Fully modular io schedulers and enables online switching between
> them was introduced in Linux 2.6.10 but as a result percentage
> of CPU using by kernel was increased and performance degradation
> is marked on Itanium. A cause of degradation is in more steps
> for indirect IO scheduler type specific function calls.
>
> The patch eliminates 45 indirect function calls in 16 elevator
> functions. Sysbench fileio benchmark throughput was increased at 2%
> for noop elevator after patching.
I don't really see the patch doing what you describe - the indirect
function calls are the same, what you did was inline the actual elevator
structure in the queue again. This breaks reference counting of said
structure, so it's not really something that can be applied. I'm
guessing what you saw was a decrease in cache misses, maybe we can do
something about that instead.
Can you say more about the throughput increase? From what to what and on
what hardware?
Oh, and your patch is totally screwed, check your mail setup.
--
Jens Axboe