* blk-mq: refactor request allocation
@ 2014-05-27 18:59 Christoph Hellwig
2014-05-27 18:59 ` [PATCH 1/5] blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request Christoph Hellwig
` (5 more replies)
0 siblings, 6 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
This series streamlines the request allocation path.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 1/5] blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
@ 2014-05-27 18:59 ` Christoph Hellwig
2014-05-27 18:59 ` [PATCH 2/5] blk-mq: initialize request in __blk_mq_alloc_request Christoph Hellwig
` (4 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
Instead of having two almost identical copies of the same code just let
the callers pass in the reserved flag directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-core.c | 2 +-
block/blk-mq.c | 20 +++-----------------
drivers/block/mtip32xx/mtip32xx.c | 2 +-
include/linux/blk-mq.h | 4 ++--
4 files changed, 7 insertions(+), 21 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 29d5fba..d87be5b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1173,7 +1173,7 @@ static struct request *blk_old_get_request(struct request_queue *q, int rw,
struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
{
if (q->mq_ops)
- return blk_mq_alloc_request(q, rw, gfp_mask);
+ return blk_mq_alloc_request(q, rw, gfp_mask, false);
else
return blk_old_get_request(q, rw, gfp_mask);
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 30bad93..f8f84e2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -294,35 +294,21 @@ static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
return rq;
}
-struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp)
+struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp,
+ bool reserved)
{
struct request *rq;
if (blk_mq_queue_enter(q))
return NULL;
- rq = blk_mq_alloc_request_pinned(q, rw, gfp, false);
+ rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved);
if (rq)
blk_mq_put_ctx(rq->mq_ctx);
return rq;
}
EXPORT_SYMBOL(blk_mq_alloc_request);
-struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw,
- gfp_t gfp)
-{
- struct request *rq;
-
- if (blk_mq_queue_enter(q))
- return NULL;
-
- rq = blk_mq_alloc_request_pinned(q, rw, gfp, true);
- if (rq)
- blk_mq_put_ctx(rq->mq_ctx);
- return rq;
-}
-EXPORT_SYMBOL(blk_mq_alloc_reserved_request);
-
static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx, struct request *rq)
{
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index ae331ab..ea323e9 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -178,7 +178,7 @@ static struct mtip_cmd *mtip_get_int_command(struct driver_data *dd)
{
struct request *rq;
- rq = blk_mq_alloc_reserved_request(dd->queue, 0, __GFP_WAIT);
+ rq = blk_mq_alloc_request(dd->queue, 0, __GFP_WAIT, true);
return blk_mq_rq_to_pdu(rq);
}
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index afeb934..2aefc3c 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -160,8 +160,8 @@ void blk_mq_insert_request(struct request *, bool, bool, bool);
void blk_mq_run_queues(struct request_queue *q, bool async);
void blk_mq_free_request(struct request *rq);
bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
-struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp);
-struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw, gfp_t gfp);
+struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
+ gfp_t gfp, bool reserved);
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag);
struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_index);
--
1.7.10.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 2/5] blk-mq: initialize request in __blk_mq_alloc_request
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
2014-05-27 18:59 ` [PATCH 1/5] blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request Christoph Hellwig
@ 2014-05-27 18:59 ` Christoph Hellwig
2014-05-27 18:59 ` [PATCH 3/5] blk-mq: remove blk_mq_wait_for_tags Christoph Hellwig
` (3 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
Both callers if __blk_mq_alloc_request want to initialize the request, so
lift it into the common path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq.c | 62 +++++++++++++++++++++++++++-----------------------------
1 file changed, 30 insertions(+), 32 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f8f84e2..848b3b6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -92,30 +92,6 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word);
}
-static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *ctx,
- gfp_t gfp, bool reserved)
-{
- struct request *rq;
- unsigned int tag;
-
- tag = blk_mq_get_tag(hctx, &ctx->last_tag, gfp, reserved);
- if (tag != BLK_MQ_TAG_FAIL) {
- rq = hctx->tags->rqs[tag];
-
- rq->cmd_flags = 0;
- if (blk_mq_tag_busy(hctx)) {
- rq->cmd_flags = REQ_MQ_INFLIGHT;
- atomic_inc(&hctx->nr_active);
- }
-
- rq->tag = tag;
- return rq;
- }
-
- return NULL;
-}
-
static int blk_mq_queue_enter(struct request_queue *q)
{
int ret;
@@ -263,6 +239,32 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
}
+static struct request *
+__blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
+ struct blk_mq_ctx *ctx, int rw, gfp_t gfp, bool reserved)
+{
+ struct request *rq;
+ unsigned int tag;
+
+ tag = blk_mq_get_tag(hctx, &ctx->last_tag, gfp, reserved);
+ if (tag != BLK_MQ_TAG_FAIL) {
+ rq = hctx->tags->rqs[tag];
+
+ rq->cmd_flags = 0;
+ if (blk_mq_tag_busy(hctx)) {
+ rq->cmd_flags = REQ_MQ_INFLIGHT;
+ atomic_inc(&hctx->nr_active);
+ }
+
+ rq->tag = tag;
+ blk_mq_rq_ctx_init(q, ctx, rq, rw);
+ return rq;
+ }
+
+ return NULL;
+}
+
+
static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
int rw, gfp_t gfp,
bool reserved)
@@ -273,12 +275,10 @@ static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);
- rq = __blk_mq_alloc_request(hctx, ctx, gfp & ~__GFP_WAIT,
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp & ~__GFP_WAIT,
reserved);
- if (rq) {
- blk_mq_rq_ctx_init(q, ctx, rq, rw);
+ if (rq)
break;
- }
if (gfp & __GFP_WAIT) {
__blk_mq_run_hw_queue(hctx);
@@ -1114,10 +1114,8 @@ static struct request *blk_mq_map_request(struct request_queue *q,
rw |= REQ_SYNC;
trace_block_getrq(q, bio, rw);
- rq = __blk_mq_alloc_request(hctx, ctx, GFP_ATOMIC, false);
- if (likely(rq))
- blk_mq_rq_ctx_init(q, ctx, rq, rw);
- else {
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw, GFP_ATOMIC, false);
+ if (unlikely(!rq)) {
blk_mq_put_ctx(ctx);
trace_block_sleeprq(q, bio, rw);
rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC,
--
1.7.10.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 3/5] blk-mq: remove blk_mq_wait_for_tags
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
2014-05-27 18:59 ` [PATCH 1/5] blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request Christoph Hellwig
2014-05-27 18:59 ` [PATCH 2/5] blk-mq: initialize request in __blk_mq_alloc_request Christoph Hellwig
@ 2014-05-27 18:59 ` Christoph Hellwig
2014-05-27 18:59 ` [PATCH 4/5] blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request Christoph Hellwig
` (2 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
The current logic for blocking tag allocation is rather confusing, as we
first allocated and then free again a tag in blk_mq_wait_for_tags, just
to attempt a non-blocking allocation and then repeat if someone else
managed to grab the tag before us.
Instead change blk_mq_alloc_request_pinned to simply do a blocking tag
allocation itself and use the request we get back from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq-tag.c | 8 --------
block/blk-mq-tag.h | 1 -
block/blk-mq.c | 13 ++++++-------
3 files changed, 6 insertions(+), 16 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 05e2baf..0d0640d 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -7,14 +7,6 @@
#include "blk-mq.h"
#include "blk-mq-tag.h"
-void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved)
-{
- int tag, zero = 0;
-
- tag = blk_mq_get_tag(hctx, &zero, __GFP_WAIT, reserved);
- blk_mq_put_tag(hctx, tag, &zero);
-}
-
static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt)
{
int i;
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 2e5e687..c959de5 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -49,7 +49,6 @@ extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int r
extern void blk_mq_free_tags(struct blk_mq_tags *tags);
extern unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved);
-extern void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved);
extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);
extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 848b3b6..44ee79c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -264,31 +264,30 @@ __blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
return NULL;
}
-
static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
int rw, gfp_t gfp,
bool reserved)
{
+ bool gfp_mask = gfp & ~__GFP_WAIT;
struct request *rq;
do {
struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);
- rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp & ~__GFP_WAIT,
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp_mask,
reserved);
if (rq)
break;
- if (gfp & __GFP_WAIT) {
- __blk_mq_run_hw_queue(hctx);
- blk_mq_put_ctx(ctx);
- } else {
+ if (!(gfp & __GFP_WAIT)) {
blk_mq_put_ctx(ctx);
break;
}
- blk_mq_wait_for_tags(hctx, reserved);
+ __blk_mq_run_hw_queue(hctx);
+ blk_mq_put_ctx(ctx);
+ gfp_mask = gfp;
} while (1);
return rq;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 4/5] blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
` (2 preceding siblings ...)
2014-05-27 18:59 ` [PATCH 3/5] blk-mq: remove blk_mq_wait_for_tags Christoph Hellwig
@ 2014-05-27 18:59 ` Christoph Hellwig
2014-05-27 18:59 ` [PATCH 5/5] blk-mq: remove blk_mq_alloc_request_pinned Christoph Hellwig
2014-05-27 20:58 ` blk-mq: refactor request allocation Jens Axboe
5 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
We already do a non-blocking allocation in blk_mq_map_request, no need
to repeat it. Just call __blk_mq_alloc_request to wait directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 44ee79c..7489d19 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1115,12 +1115,14 @@ static struct request *blk_mq_map_request(struct request_queue *q,
trace_block_getrq(q, bio, rw);
rq = __blk_mq_alloc_request(q, hctx, ctx, rw, GFP_ATOMIC, false);
if (unlikely(!rq)) {
+ __blk_mq_run_hw_queue(hctx);
blk_mq_put_ctx(ctx);
trace_block_sleeprq(q, bio, rw);
- rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC,
- false);
- ctx = rq->mq_ctx;
+
+ ctx = blk_mq_get_ctx(q);
hctx = q->mq_ops->map_queue(q, ctx->cpu);
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw,
+ __GFP_WAIT|GFP_ATOMIC, false);
}
hctx->queued++;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 5/5] blk-mq: remove blk_mq_alloc_request_pinned
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
` (3 preceding siblings ...)
2014-05-27 18:59 ` [PATCH 4/5] blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request Christoph Hellwig
@ 2014-05-27 18:59 ` Christoph Hellwig
2014-05-27 20:58 ` blk-mq: refactor request allocation Jens Axboe
5 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-27 18:59 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
We now only have one caller left and can open code it there in a cleaner
way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq.c | 48 ++++++++++++++++--------------------------------
1 file changed, 16 insertions(+), 32 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7489d19..9d27077 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -264,46 +264,30 @@ __blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
return NULL;
}
-static struct request *blk_mq_alloc_request_pinned(struct request_queue *q,
- int rw, gfp_t gfp,
- bool reserved)
-{
- bool gfp_mask = gfp & ~__GFP_WAIT;
- struct request *rq;
-
- do {
- struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
- struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu);
-
- rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp_mask,
- reserved);
- if (rq)
- break;
-
- if (!(gfp & __GFP_WAIT)) {
- blk_mq_put_ctx(ctx);
- break;
- }
-
- __blk_mq_run_hw_queue(hctx);
- blk_mq_put_ctx(ctx);
- gfp_mask = gfp;
- } while (1);
-
- return rq;
-}
-
struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp,
bool reserved)
{
+ struct blk_mq_ctx *ctx;
+ struct blk_mq_hw_ctx *hctx;
struct request *rq;
if (blk_mq_queue_enter(q))
return NULL;
- rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved);
- if (rq)
- blk_mq_put_ctx(rq->mq_ctx);
+ ctx = blk_mq_get_ctx(q);
+ hctx = q->mq_ops->map_queue(q, ctx->cpu);
+
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp & ~__GFP_WAIT,
+ reserved);
+ if (!rq && (gfp & __GFP_WAIT)) {
+ __blk_mq_run_hw_queue(hctx);
+ blk_mq_put_ctx(ctx);
+
+ ctx = blk_mq_get_ctx(q);
+ hctx = q->mq_ops->map_queue(q, ctx->cpu);
+ rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp, reserved);
+ }
+ blk_mq_put_ctx(ctx);
return rq;
}
EXPORT_SYMBOL(blk_mq_alloc_request);
--
1.7.10.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: blk-mq: refactor request allocation
2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
` (4 preceding siblings ...)
2014-05-27 18:59 ` [PATCH 5/5] blk-mq: remove blk_mq_alloc_request_pinned Christoph Hellwig
@ 2014-05-27 20:58 ` Jens Axboe
2014-05-28 5:19 ` Christoph Hellwig
5 siblings, 1 reply; 10+ messages in thread
From: Jens Axboe @ 2014-05-27 20:58 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-kernel
On 05/27/2014 12:59 PM, Christoph Hellwig wrote:
> This series streamlines the request allocation path.
>
Series looks innocuous enough to me, but it's about a 1.5% performance
drop here with an actual device. These tests are very stable, anything
over ~0.1% is definitely outside of noise. I repeated and rebooted a few
times and tested both, it's persistent. No smoking guns in the profile.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: blk-mq: refactor request allocation
2014-05-27 20:58 ` blk-mq: refactor request allocation Jens Axboe
@ 2014-05-28 5:19 ` Christoph Hellwig
2014-05-28 14:20 ` Jens Axboe
2014-05-28 15:47 ` Jens Axboe
0 siblings, 2 replies; 10+ messages in thread
From: Christoph Hellwig @ 2014-05-28 5:19 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
On Tue, May 27, 2014 at 02:58:08PM -0600, Jens Axboe wrote:
> On 05/27/2014 12:59 PM, Christoph Hellwig wrote:
> > This series streamlines the request allocation path.
> >
>
> Series looks innocuous enough to me, but it's about a 1.5% performance
> drop here with an actual device. These tests are very stable, anything
> over ~0.1% is definitely outside of noise. I repeated and rebooted a few
> times and tested both, it's persistent. No smoking guns in the profile.
Can you do a bisect to narrow it down to one of the patches?
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: blk-mq: refactor request allocation
2014-05-28 5:19 ` Christoph Hellwig
@ 2014-05-28 14:20 ` Jens Axboe
2014-05-28 15:47 ` Jens Axboe
1 sibling, 0 replies; 10+ messages in thread
From: Jens Axboe @ 2014-05-28 14:20 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-kernel
On 2014-05-27 23:19, Christoph Hellwig wrote:
> On Tue, May 27, 2014 at 02:58:08PM -0600, Jens Axboe wrote:
>> On 05/27/2014 12:59 PM, Christoph Hellwig wrote:
>>> This series streamlines the request allocation path.
>>>
>>
>> Series looks innocuous enough to me, but it's about a 1.5% performance
>> drop here with an actual device. These tests are very stable, anything
>> over ~0.1% is definitely outside of noise. I repeated and rebooted a few
>> times and tested both, it's persistent. No smoking guns in the profile.
>
> Can you do a bisect to narrow it down to one of the patches?
Sure, I'll give it a whirl.
--
Jens Axboe
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: blk-mq: refactor request allocation
2014-05-28 5:19 ` Christoph Hellwig
2014-05-28 14:20 ` Jens Axboe
@ 2014-05-28 15:47 ` Jens Axboe
1 sibling, 0 replies; 10+ messages in thread
From: Jens Axboe @ 2014-05-28 15:47 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-kernel
On 2014-05-27 23:19, Christoph Hellwig wrote:
> On Tue, May 27, 2014 at 02:58:08PM -0600, Jens Axboe wrote:
>> On 05/27/2014 12:59 PM, Christoph Hellwig wrote:
>>> This series streamlines the request allocation path.
>>>
>>
>> Series looks innocuous enough to me, but it's about a 1.5% performance
>> drop here with an actual device. These tests are very stable, anything
>> over ~0.1% is definitely outside of noise. I repeated and rebooted a few
>> times and tested both, it's persistent. No smoking guns in the profile.
>
> Can you do a bisect to narrow it down to one of the patches?
Did bisect and even one-by-one, and now it doesn't show up of course.
The nvme branch was rebased on top of a new base since yesterday, so it
could just be layout weirdness from the previous one.
So I think we can call it fine, I'll apply it.
--
Jens Axboe
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2014-05-28 15:47 UTC | newest]
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2014-05-27 18:59 blk-mq: refactor request allocation Christoph Hellwig
2014-05-27 18:59 ` [PATCH 1/5] blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request Christoph Hellwig
2014-05-27 18:59 ` [PATCH 2/5] blk-mq: initialize request in __blk_mq_alloc_request Christoph Hellwig
2014-05-27 18:59 ` [PATCH 3/5] blk-mq: remove blk_mq_wait_for_tags Christoph Hellwig
2014-05-27 18:59 ` [PATCH 4/5] blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request Christoph Hellwig
2014-05-27 18:59 ` [PATCH 5/5] blk-mq: remove blk_mq_alloc_request_pinned Christoph Hellwig
2014-05-27 20:58 ` blk-mq: refactor request allocation Jens Axboe
2014-05-28 5:19 ` Christoph Hellwig
2014-05-28 14:20 ` Jens Axboe
2014-05-28 15:47 ` Jens Axboe
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