Commit 59d9136b authored by Benjamin LaHaise's avatar Benjamin LaHaise Committed by Linus Torvalds

[PATCH] aio: reorder kiocb structure elements to make sync iocb setup faster

Reorder members of the kiocb structure to make sync kiocb setup faster.  By
setting the elements sequentially, the write combining buffers on the CPU
are able to combine the writes into a single burst, which results in fewer
cache cycles being consumed, freeing them up for other code.  This results
in a 10-20KB/s[*] increase on the bw_unix part of LMbench on my test
system.

* The improvement varies based on what other patches are in the system,
  as there are a number of bottlenecks, so this number is not absolutely
  accurate.
Signed-off-by: default avatarBenjamin LaHaise <benjamin.c.lahaise@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fb169793
...@@ -94,26 +94,27 @@ struct kiocb { ...@@ -94,26 +94,27 @@ struct kiocb {
ssize_t (*ki_retry)(struct kiocb *); ssize_t (*ki_retry)(struct kiocb *);
void (*ki_dtor)(struct kiocb *); void (*ki_dtor)(struct kiocb *);
struct list_head ki_list; /* the aio core uses this
* for cancellation */
union { union {
void __user *user; void __user *user;
struct task_struct *tsk; struct task_struct *tsk;
} ki_obj; } ki_obj;
__u64 ki_user_data; /* user's data for completion */ __u64 ki_user_data; /* user's data for completion */
wait_queue_t ki_wait;
loff_t ki_pos; loff_t ki_pos;
void *private;
/* State that we remember to be able to restart/retry */ /* State that we remember to be able to restart/retry */
unsigned short ki_opcode; unsigned short ki_opcode;
size_t ki_nbytes; /* copy of iocb->aio_nbytes */ size_t ki_nbytes; /* copy of iocb->aio_nbytes */
char __user *ki_buf; /* remaining iocb->aio_buf */ char __user *ki_buf; /* remaining iocb->aio_buf */
size_t ki_left; /* remaining bytes */ size_t ki_left; /* remaining bytes */
wait_queue_t ki_wait;
long ki_retried; /* just for testing */ long ki_retried; /* just for testing */
long ki_kicked; /* just for testing */ long ki_kicked; /* just for testing */
long ki_queued; /* just for testing */ long ki_queued; /* just for testing */
void *private; struct list_head ki_list; /* the aio core uses this
* for cancellation */
}; };
#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY) #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
...@@ -126,6 +127,7 @@ struct kiocb { ...@@ -126,6 +127,7 @@ struct kiocb {
(x)->ki_filp = (filp); \ (x)->ki_filp = (filp); \
(x)->ki_ctx = NULL; \ (x)->ki_ctx = NULL; \
(x)->ki_cancel = NULL; \ (x)->ki_cancel = NULL; \
(x)->ki_retry = NULL; \
(x)->ki_dtor = NULL; \ (x)->ki_dtor = NULL; \
(x)->ki_obj.tsk = tsk; \ (x)->ki_obj.tsk = tsk; \
(x)->ki_user_data = 0; \ (x)->ki_user_data = 0; \
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment