Nick Piggin wrote:
Aside from using branch constructs or hints that help the predictor
guess the right way... I think gcc will move unlikely paths right past
the end of the "likely" fastpath, so it can increase code size and be
somewhat suboptimal in terms of icache usage.
Thanks for the
Jeff Garzik wrote:
Andrew Morton wrote:
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi <[EMAIL PROTECTED]> wrote:
But as Jeff said, that's not what unlikely is for. It should only be
used when it is unlikely for everybody, all the time, because when it
is right, it helps rather little,
Andrew Morton wrote:
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi <[EMAIL PROTECTED]> wrote:
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi <[EMAIL PROTECTED]> wrote:
> Andrew Morton wrote:
> > Yes, if you agree with Jeff's original point.
> >
> > But I don't, actually. Sure, on some machines+workloads, AIO is more
> > common than sync IO. But I expect that when we sum across all the
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across all the
machines+workloads in the world, sync IO is more common and is hence the
case we should
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across all the
machines+workloads in the world, sync IO is more common and is hence the
case we should
On Fri, 18 May 2007 16:49:49 -0400
"Alex Volkov" <[EMAIL PROTECTED]> wrote:
>
> Andrew Morton wrote:
> > aio is unlikely
> > Stick an unlikely() around is_aio(): I assert that most IO is
> synchronous.
> >
> > -#define in_aio() !i
Andrew Morton wrote:
> aio is unlikely
> Stick an unlikely() around is_aio(): I assert that most IO is
synchronous.
>
> -#define in_aio() !is_sync_wait(current->io_wait)
> +#define in_aio() (unlikely(!is_sync_wait(current->io_wait)))
> Jeff Garzik &
Andrew Morton wrote:
aio is unlikely
Stick an unlikely() around is_aio(): I assert that most IO is
synchronous.
-#define in_aio() !is_sync_wait(current-io_wait)
+#define in_aio() (unlikely(!is_sync_wait(current-io_wait)))
Jeff Garzik [EMAIL PROTECTED] wrote:
-#define in_aio
On Fri, 18 May 2007 16:49:49 -0400
Alex Volkov [EMAIL PROTECTED] wrote:
Andrew Morton wrote:
aio is unlikely
Stick an unlikely() around is_aio(): I assert that most IO is
synchronous.
-#define in_aio() !is_sync_wait(current-io_wait)
+#define in_aio() (unlikely(!is_sync_wait
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across all the
machines+workloads in the world, sync IO is more common and is hence the
case we should
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across all the
machines+workloads in the world, sync IO is more common and is hence the
case we should
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi [EMAIL PROTECTED] wrote:
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across all the
Andrew Morton wrote:
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi [EMAIL PROTECTED] wrote:
Andrew Morton wrote:
Yes, if you agree with Jeff's original point.
But I don't, actually. Sure, on some machines+workloads, AIO is more
common than sync IO. But I expect that when we sum across
Jeff Garzik wrote:
Andrew Morton wrote:
On Fri, 18 May 2007 17:54:32 -0400
Phillip Susi [EMAIL PROTECTED] wrote:
But as Jeff said, that's not what unlikely is for. It should only be
used when it is unlikely for everybody, all the time, because when it
is right, it helps rather little, but
Nick Piggin wrote:
Aside from using branch constructs or hints that help the predictor
guess the right way... I think gcc will move unlikely paths right past
the end of the likely fastpath, so it can increase code size and be
somewhat suboptimal in terms of icache usage.
Thanks for the
Andrew Morton wrote:
a) disagree with the above
b) if in_aio() ever returns true we do
printk(KERN_ERR "%s(%s:%d) called in async context!\n",
__FUNCTION__, __FILE__, __LINE__);
so I sure hope it's unlikely for all workloads.
hrm, indeed. Ignore me.
On Wed, 09 May 2007 18:06:58 -0400
Jeff Garzik <[EMAIL PROTECTED]> wrote:
> > -#define in_aio() !is_sync_wait(current->io_wait)
> > +#define in_aio() (unlikely(!is_sync_wait(current->io_wait)))
>
> Please revert. Workload-dependent "likelihood" should not cause
> programmers to add such
Morton <[EMAIL PROTECTED]>
AuthorDate: Wed May 9 02:34:58 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed May 9 12:30:54 2007 -0700
aio is unlikely
Stick an unlikely() around is_aio(): I assert that most IO is synchronous.
Cc: Suparna Bhattach
Morton [EMAIL PROTECTED]
AuthorDate: Wed May 9 02:34:58 2007 -0700
Committer: Linus Torvalds [EMAIL PROTECTED]
CommitDate: Wed May 9 12:30:54 2007 -0700
aio is unlikely
Stick an unlikely() around is_aio(): I assert that most IO is synchronous.
Cc: Suparna Bhattacharya [EMAIL
On Wed, 09 May 2007 18:06:58 -0400
Jeff Garzik [EMAIL PROTECTED] wrote:
-#define in_aio() !is_sync_wait(current-io_wait)
+#define in_aio() (unlikely(!is_sync_wait(current-io_wait)))
Please revert. Workload-dependent likelihood should not cause
programmers to add such markers.
This is
Andrew Morton wrote:
a) disagree with the above
b) if in_aio() ever returns true we do
printk(KERN_ERR %s(%s:%d) called in async context!\n,
__FUNCTION__, __FILE__, __LINE__);
so I sure hope it's unlikely for all workloads.
hrm, indeed. Ignore me.
Jeff
22 matches
Mail list logo