2011-03-04 06:17:09

by Tao Ma

Subject: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

From: Tao Ma <[email protected]>

In blk_add_trace_rq, we only chose the minor 2 bits from
request's cmd_flags and did some check for discard.
so most of other flags(e.g, REQ_SYNC) are missing.

For example, with a sync write after blkparse we get:
8,16 1 1 0.001776503 7509 A WS 1349632 + 1024 <- (8,17) 1347584
8,16 1 2 0.001776813 7509 Q WS 1349632 + 1024 [dd]
8,16 1 3 0.001780395 7509 G WS 1349632 + 1024 [dd]
8,16 1 5 0.001783186 7509 I W 1349632 + 1024 [dd]
8,16 1 11 0.001816987 7509 D W 1349632 + 1024 [dd]
8,16 0 2 0.006218192 0 C W 1349632 + 1024 [0]

Since now we have integrated the flags of both bio and request,
it is safe to pass rq->cmd_flags directly to __blk_add_trace.

With this patch, after a sync write we get:
8,16 1 1 0.001776900 5425 A WS 1189888 + 1024 <- (8,17) 1187840
8,16 1 2 0.001777179 5425 Q WS 1189888 + 1024 [dd]
8,16 1 3 0.001780797 5425 G WS 1189888 + 1024 [dd]
8,16 1 5 0.001783402 5425 I WS 1189888 + 1024 [dd]
8,16 1 11 0.001817468 5425 D WS 1189888 + 1024 [dd]
8,16 0 2 0.005640709 0 C WS 1189888 + 1024 [0]

Cc: Jens Axboe <[email protected]>
Signed-off-by: Tao Ma <[email protected]>
---
kernel/trace/blktrace.c | 15 ++++-----------
1 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index cbafed7..7aa40f8 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q)
*
**/
static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
- u32 what)
+ u32 what)
{
struct blk_trace *bt = q->blk_trace;
- int rw = rq->cmd_flags & 0x03;

if (likely(!bt))
return;

- if (rq->cmd_flags & REQ_DISCARD)
- rw |= REQ_DISCARD;
-
- if (rq->cmd_flags & REQ_SECURE)
- rw |= REQ_SECURE;
-
if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
what |= BLK_TC_ACT(BLK_TC_PC);
- __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
+ __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
what, rq->errors, rq->cmd_len, rq->cmd);
} else {
what |= BLK_TC_ACT(BLK_TC_FS);
- __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
- what, rq->errors, 0, NULL);
+ __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+ rq->cmd_flags, what, rq->errors, 0, NULL);
}
}

--
1.6.3.GIT

2011-03-09 14:06:21

by Tao Ma

Subject: Re: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

Hi Jens and Jeff,
any comment for this?
It should be similar as patch 2d3a8497, but a fix to the real blktrace.

Regards,
Tao

On 03/04/2011 02:15 PM, Tao Ma wrote:
> From: Tao Ma<[email protected]>
>
> In blk_add_trace_rq, we only chose the minor 2 bits from
> request's cmd_flags and did some check for discard.
> so most of other flags(e.g, REQ_SYNC) are missing.
>
> For example, with a sync write after blkparse we get:
> 8,16 1 1 0.001776503 7509 A WS 1349632 + 1024<- (8,17) 1347584
> 8,16 1 2 0.001776813 7509 Q WS 1349632 + 1024 [dd]
> 8,16 1 3 0.001780395 7509 G WS 1349632 + 1024 [dd]
> 8,16 1 5 0.001783186 7509 I W 1349632 + 1024 [dd]
> 8,16 1 11 0.001816987 7509 D W 1349632 + 1024 [dd]
> 8,16 0 2 0.006218192 0 C W 1349632 + 1024 [0]
>
> Since now we have integrated the flags of both bio and request,
> it is safe to pass rq->cmd_flags directly to __blk_add_trace.
>
> With this patch, after a sync write we get:
> 8,16 1 1 0.001776900 5425 A WS 1189888 + 1024<- (8,17) 1187840
> 8,16 1 2 0.001777179 5425 Q WS 1189888 + 1024 [dd]
> 8,16 1 3 0.001780797 5425 G WS 1189888 + 1024 [dd]
> 8,16 1 5 0.001783402 5425 I WS 1189888 + 1024 [dd]
> 8,16 1 11 0.001817468 5425 D WS 1189888 + 1024 [dd]
> 8,16 0 2 0.005640709 0 C WS 1189888 + 1024 [0]
>
> Cc: Jens Axboe<[email protected]>
> Signed-off-by: Tao Ma<[email protected]>
> ---
> kernel/trace/blktrace.c | 15 ++++-----------
> 1 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index cbafed7..7aa40f8 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q)
> *
> **/
> static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
> - u32 what)
> + u32 what)
> {
> struct blk_trace *bt = q->blk_trace;
> - int rw = rq->cmd_flags& 0x03;
>
> if (likely(!bt))
> return;
>
> - if (rq->cmd_flags& REQ_DISCARD)
> - rw |= REQ_DISCARD;
> -
> - if (rq->cmd_flags& REQ_SECURE)
> - rw |= REQ_SECURE;
> -
> if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
> what |= BLK_TC_ACT(BLK_TC_PC);
> - __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
> + __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
> what, rq->errors, rq->cmd_len, rq->cmd);
> } else {
> what |= BLK_TC_ACT(BLK_TC_FS);
> - __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
> - what, rq->errors, 0, NULL);
> + __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
> + rq->cmd_flags, what, rq->errors, 0, NULL);
> }
> }
>

2011-03-09 14:31:12

by Jeff Moyer

Subject: Re: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

Tao Ma <[email protected]> writes:

> From: Tao Ma <[email protected]>
>
> In blk_add_trace_rq, we only chose the minor 2 bits from
> request's cmd_flags and did some check for discard.
> so most of other flags(e.g, REQ_SYNC) are missing.
>
> For example, with a sync write after blkparse we get:
> 8,16 1 1 0.001776503 7509 A WS 1349632 + 1024 <- (8,17) 1347584
> 8,16 1 2 0.001776813 7509 Q WS 1349632 + 1024 [dd]
> 8,16 1 3 0.001780395 7509 G WS 1349632 + 1024 [dd]
> 8,16 1 5 0.001783186 7509 I W 1349632 + 1024 [dd]
> 8,16 1 11 0.001816987 7509 D W 1349632 + 1024 [dd]
> 8,16 0 2 0.006218192 0 C W 1349632 + 1024 [0]
>
> Since now we have integrated the flags of both bio and request,
> it is safe to pass rq->cmd_flags directly to __blk_add_trace.
>
> With this patch, after a sync write we get:
> 8,16 1 1 0.001776900 5425 A WS 1189888 + 1024 <- (8,17) 1187840
> 8,16 1 2 0.001777179 5425 Q WS 1189888 + 1024 [dd]
> 8,16 1 3 0.001780797 5425 G WS 1189888 + 1024 [dd]
> 8,16 1 5 0.001783402 5425 I WS 1189888 + 1024 [dd]
> 8,16 1 11 0.001817468 5425 D WS 1189888 + 1024 [dd]
> 8,16 0 2 0.005640709 0 C WS 1189888 + 1024 [0]
>
> Cc: Jens Axboe <[email protected]>
> Signed-off-by: Tao Ma <[email protected]>
> ---
> kernel/trace/blktrace.c | 15 ++++-----------
> 1 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index cbafed7..7aa40f8 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q)
> *
> **/
> static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
> - u32 what)
> + u32 what)
> {
> struct blk_trace *bt = q->blk_trace;
> - int rw = rq->cmd_flags & 0x03;
>
> if (likely(!bt))
> return;
>
> - if (rq->cmd_flags & REQ_DISCARD)
> - rw |= REQ_DISCARD;
> -
> - if (rq->cmd_flags & REQ_SECURE)
> - rw |= REQ_SECURE;
> -
> if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
> what |= BLK_TC_ACT(BLK_TC_PC);
> - __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
> + __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
> what, rq->errors, rq->cmd_len, rq->cmd);
> } else {
> what |= BLK_TC_ACT(BLK_TC_FS);
> - __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
> - what, rq->errors, 0, NULL);
> + __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
> + rq->cmd_flags, what, rq->errors, 0, NULL);
> }
> }

Looks like a fine cleanup to me.

Acked-by: Jeff Moyer <[email protected]>

2011-03-11 19:12:44

by Jens Axboe

Subject: Re: [PATCH] blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.

On 2011-03-04 07:15, Tao Ma wrote:
> From: Tao Ma <[email protected]>
>
> In blk_add_trace_rq, we only chose the minor 2 bits from
> request's cmd_flags and did some check for discard.
> so most of other flags(e.g, REQ_SYNC) are missing.
>
> For example, with a sync write after blkparse we get:
> 8,16 1 1 0.001776503 7509 A WS 1349632 + 1024 <- (8,17) 1347584
> 8,16 1 2 0.001776813 7509 Q WS 1349632 + 1024 [dd]
> 8,16 1 3 0.001780395 7509 G WS 1349632 + 1024 [dd]
> 8,16 1 5 0.001783186 7509 I W 1349632 + 1024 [dd]
> 8,16 1 11 0.001816987 7509 D W 1349632 + 1024 [dd]
> 8,16 0 2 0.006218192 0 C W 1349632 + 1024 [0]
>
> Since now we have integrated the flags of both bio and request,
> it is safe to pass rq->cmd_flags directly to __blk_add_trace.
>
> With this patch, after a sync write we get:
> 8,16 1 1 0.001776900 5425 A WS 1189888 + 1024 <- (8,17) 1187840
> 8,16 1 2 0.001777179 5425 Q WS 1189888 + 1024 [dd]
> 8,16 1 3 0.001780797 5425 G WS 1189888 + 1024 [dd]
> 8,16 1 5 0.001783402 5425 I WS 1189888 + 1024 [dd]
> 8,16 1 11 0.001817468 5425 D WS 1189888 + 1024 [dd]
> 8,16 0 2 0.005640709 0 C WS 1189888 + 1024 [0]

Thanks, applied!

--
Jens Axboe