* [pathch] kernel/sched.c bogon?
@ 2003-03-07 1:01 Kip Walker
2003-03-07 1:40 ` Jun Sun
2003-04-25 15:28 ` Kip Walker
0 siblings, 2 replies; 6+ messages in thread
From: Kip Walker @ 2003-03-07 1:01 UTC (permalink / raw)
To: linux-mips
The comparisons of oldest_idle below trigger compiler warnings and
should probably be safely type-cast:
Kip
Index: kernel/sched.c
===================================================================
RCS file: /home/cvs/linux/kernel/sched.c,v
retrieving revision 1.64.2.6
diff -u -r1.64.2.6 sched.c
--- kernel/sched.c 25 Feb 2003 22:03:13 -0000 1.64.2.6
+++ kernel/sched.c 7 Mar 2003 00:57:35 -0000
@@ -282,7 +282,7 @@
target_tsk = tsk;
}
} else {
- if (oldest_idle == -1ULL) {
+ if (oldest_idle == (cycles_t) -1) {
int prio = preemption_goodness(tsk, p,
cpu);
if (prio > max_prio) {
@@ -294,7 +294,7 @@
}
tsk = target_tsk;
if (tsk) {
- if (oldest_idle != -1ULL) {
+ if (oldest_idle != (cycles_t) -1) {
best_cpu = tsk->processor;
goto send_now_idle;
}
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [pathch] kernel/sched.c bogon?
2003-03-07 1:01 [pathch] kernel/sched.c bogon? Kip Walker
@ 2003-03-07 1:40 ` Jun Sun
2003-03-10 12:55 ` Ralf Baechle
2003-04-25 15:28 ` Kip Walker
1 sibling, 1 reply; 6+ messages in thread
From: Jun Sun @ 2003-03-07 1:40 UTC (permalink / raw)
To: Kip Walker; +Cc: linux-mips, jsun
I reported this bug last May. Apparently it is still not
taken up-stream. Ralf, why don't we fix it here and push
it up from you?
BTW, this bug actually has effect on real-time performance under
preemptible kernel. It can delay the execution of the highest
priority real-time process from execution up to 1 jiffy.
Jun
On Thu, Mar 06, 2003 at 05:01:24PM -0800, Kip Walker wrote:
>
> The comparisons of oldest_idle below trigger compiler warnings and
> should probably be safely type-cast:
>
> Kip
>
> Index: kernel/sched.c
> ===================================================================
> RCS file: /home/cvs/linux/kernel/sched.c,v
> retrieving revision 1.64.2.6
> diff -u -r1.64.2.6 sched.c
> --- kernel/sched.c 25 Feb 2003 22:03:13 -0000 1.64.2.6
> +++ kernel/sched.c 7 Mar 2003 00:57:35 -0000
> @@ -282,7 +282,7 @@
> target_tsk = tsk;
> }
> } else {
> - if (oldest_idle == -1ULL) {
> + if (oldest_idle == (cycles_t) -1) {
> int prio = preemption_goodness(tsk, p,
> cpu);
>
> if (prio > max_prio) {
> @@ -294,7 +294,7 @@
> }
> tsk = target_tsk;
> if (tsk) {
> - if (oldest_idle != -1ULL) {
> + if (oldest_idle != (cycles_t) -1) {
> best_cpu = tsk->processor;
> goto send_now_idle;
> }
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [pathch] kernel/sched.c bogon?
2003-03-07 1:40 ` Jun Sun
@ 2003-03-10 12:55 ` Ralf Baechle
2003-03-10 17:59 ` Jun Sun
0 siblings, 1 reply; 6+ messages in thread
From: Ralf Baechle @ 2003-03-10 12:55 UTC (permalink / raw)
To: Jun Sun; +Cc: Kip Walker, linux-mips
On Thu, Mar 06, 2003 at 05:40:01PM -0800, Jun Sun wrote:
> I reported this bug last May. Apparently it is still not
> taken up-stream. Ralf, why don't we fix it here and push
> it up from you?
>
> BTW, this bug actually has effect on real-time performance under
> preemptible kernel.
< = 2.4.x preemptible kernel is OPP.
> It can delay the execution of the highest
> priority real-time process from execution up to 1 jiffy.
Quite a number of users get_cycles() in the kernel assume it to return a
64-bit number. I guess we'll have to fake a 64-bit counter in software ...
Ralf
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pathch] kernel/sched.c bogon?
2003-03-10 12:55 ` Ralf Baechle
@ 2003-03-10 17:59 ` Jun Sun
2003-04-24 17:03 ` Kip Walker
0 siblings, 1 reply; 6+ messages in thread
From: Jun Sun @ 2003-03-10 17:59 UTC (permalink / raw)
To: Ralf Baechle; +Cc: Kip Walker, linux-mips, jsun
On Mon, Mar 10, 2003 at 01:55:31PM +0100, Ralf Baechle wrote:
> On Thu, Mar 06, 2003 at 05:40:01PM -0800, Jun Sun wrote:
>
> > I reported this bug last May. Apparently it is still not
> > taken up-stream. Ralf, why don't we fix it here and push
> > it up from you?
> >
> > BTW, this bug actually has effect on real-time performance under
> > preemptible kernel.
>
> < = 2.4.x preemptible kernel is OPP.
>
> > It can delay the execution of the highest
> > priority real-time process from execution up to 1 jiffy.
>
> Quite a number of users get_cycles() in the kernel assume it to return a
> 64-bit number. I guess we'll have to fake a 64-bit counter in software ...
>
Whether we fake 64-bit or not, oldest_idle is declared as cycles_t.
So comparing it with (cycles_t)-1 should be always be correct. And it
actually makes a correct C program. :-)
I don't see any possible reason for rejecting the change. My previous
report is probably just lost in the noise.
Jun
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pathch] kernel/sched.c bogon?
2003-03-10 17:59 ` Jun Sun
@ 2003-04-24 17:03 ` Kip Walker
0 siblings, 0 replies; 6+ messages in thread
From: Kip Walker @ 2003-04-24 17:03 UTC (permalink / raw)
To: Jun Sun; +Cc: Ralf Baechle, linux-mips
Jun Sun wrote:
>
> On Mon, Mar 10, 2003 at 01:55:31PM +0100, Ralf Baechle wrote:
> > On Thu, Mar 06, 2003 at 05:40:01PM -0800, Jun Sun wrote:
> >
> > > I reported this bug last May. Apparently it is still not
> > > taken up-stream. Ralf, why don't we fix it here and push
> > > it up from you?
> > >
> > > BTW, this bug actually has effect on real-time performance under
> > > preemptible kernel.
> >
> > < = 2.4.x preemptible kernel is OPP.
> >
> > > It can delay the execution of the highest
> > > priority real-time process from execution up to 1 jiffy.
> >
> > Quite a number of users get_cycles() in the kernel assume it to return a
> > 64-bit number. I guess we'll have to fake a 64-bit counter in software ...
> >
>
> Whether we fake 64-bit or not, oldest_idle is declared as cycles_t.
> So comparing it with (cycles_t)-1 should be always be correct. And it
> actually makes a correct C program. :-)
>
> I don't see any possible reason for rejecting the change. My previous
> report is probably just lost in the noise.
And once again, the patch hasn't made it in. Can we either apply it get
a good reason not to?
Kip
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pathch] kernel/sched.c bogon?
2003-03-07 1:01 [pathch] kernel/sched.c bogon? Kip Walker
2003-03-07 1:40 ` Jun Sun
@ 2003-04-25 15:28 ` Kip Walker
1 sibling, 0 replies; 6+ messages in thread
From: Kip Walker @ 2003-04-25 15:28 UTC (permalink / raw)
To: linux-mips
Ralf? I'm tying up loose ends between my tree and yours, and hoping to
push some things back.
Kip Walker wrote:
>
> The comparisons of oldest_idle below trigger compiler warnings and
> should probably be safely type-cast:
>
> Kip
>
> Index: kernel/sched.c
> ===================================================================
> RCS file: /home/cvs/linux/kernel/sched.c,v
> retrieving revision 1.64.2.6
> diff -u -r1.64.2.6 sched.c
> --- kernel/sched.c 25 Feb 2003 22:03:13 -0000 1.64.2.6
> +++ kernel/sched.c 7 Mar 2003 00:57:35 -0000
> @@ -282,7 +282,7 @@
> target_tsk = tsk;
> }
> } else {
> - if (oldest_idle == -1ULL) {
> + if (oldest_idle == (cycles_t) -1) {
> int prio = preemption_goodness(tsk, p,
> cpu);
>
> if (prio > max_prio) {
> @@ -294,7 +294,7 @@
> }
> tsk = target_tsk;
> if (tsk) {
> - if (oldest_idle != -1ULL) {
> + if (oldest_idle != (cycles_t) -1) {
> best_cpu = tsk->processor;
> goto send_now_idle;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2003-04-25 15:28 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-03-07 1:01 [pathch] kernel/sched.c bogon? Kip Walker
2003-03-07 1:40 ` Jun Sun
2003-03-10 12:55 ` Ralf Baechle
2003-03-10 17:59 ` Jun Sun
2003-04-24 17:03 ` Kip Walker
2003-04-25 15:28 ` Kip Walker
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox