[patch] O(1) scheduler, -H4 - 2.4.17 problems

[patch] O(1) scheduler, -H4 - 2.4.17 problems

[Ed Tomlinson]

Hi,

The H4 sceduler does not boot here.  The G1 version worked.  The H4 version gets
as far as:

PCI: Using IRQ router VIA [1106/0586] at 00:07.0
Activating ISA DMA hang workarounds.
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket

and Stalls.  next messages are normally 

Starting kswapd
matroxfb: Matrox Millennium G400 MAX (AGP) detected
matroxfb: MTRR's turned on
matroxfb: 640x480x8bpp (virtual: 640x26208)
matroxfb: framebuffer at 0xE8000000, mapped to 0xe0805000, size 33554432
Console: switching to colour frame buffer device 80x30

The rmap11 patch is also installed with the follow patch used to resolve the conflict.
I have been using this varient since E1.

Incase I messed up removing and repatch I tried from a clean kernel with the same results.
Any one else seeing this?

Box is K6-III 400.

Ed Tomlinson

--- linux/mm/page_alloc.c.rmap	Tue Jan  8 18:24:10 2002
+++ linux/mm/page_alloc.c	Tue Jan  8 18:25:00 2002
@@ -471,9 +471,7 @@
 		 * NFS: we must yield the CPU (to rpciod) to avoid deadlock.
 		 */
 		if (gfp_mask & __GFP_WAIT) {
-			__set_current_state(TASK_RUNNING);
-			current->policy |= SCHED_YIELD;
-			schedule();
+			yield();
 			if (!order || free_high(ALL_ZONES) >= 0) {
 				int progress = try_to_free_pages(gfp_mask);
 				if (progress || (gfp_mask & __GFP_FS))
--- linux/include/linux/sched.h.rmap	Tue Jan  8 18:28:15 2002
+++ linux/include/linux/sched.h	Tue Jan  8 18:33:36 2002
@@ -298,34 +298,50 @@
 
 	int lock_depth;		/* Lock depth */
 
-/*
- * offset 32 begins here on 32-bit platforms. We keep
- * all fields in a single cacheline that are needed for
- * the goodness() loop in schedule().
- */
-	long counter;
-	long nice;
-	unsigned long policy;
-	struct mm_struct *mm;
-	int processor;
 	/*
-	 * cpus_runnable is ~0 if the process is not running on any
-	 * CPU. It's (1 << cpu) if it's running on a CPU. This mask
-	 * is updated under the runqueue lock.
-	 *
-	 * To determine whether a process might run on a CPU, this
-	 * mask is AND-ed with cpus_allowed.
+         * offset 32 begins here on 32-bit platforms.
 	 */
-	unsigned long cpus_runnable, cpus_allowed;
+        unsigned int cpu;
+        int prio;
+        long __nice;
+        list_t run_list;
+        prio_array_t *array;
+ 
+        unsigned int time_slice;
+        unsigned long sleep_timestamp, run_timestamp;
+
 	/*
-	 * (only the 'next' pointer fits into the cacheline, but
-	 * that's just fine.)
+         * A task's four 'sleep history' entries.
+         *
+         * We track the last 4 seconds of time. (including the current second).
+         *
+         * A value of '0' means it has spent no time sleeping in that
+         * particular past second. The maximum value of 'HZ' means that
+         * the task spent all its time running in that particular second.
+         *
+         * 'hist_idx' points to the current second, which, unlike the other
+         * 3 entries, is only partially complete. This means that a value of
+         * '25' does not mean the task slept 25% of the time in the current
+         * second, it means that it spent 25 timer ticks sleeping in the
+         * current second.
+         *
+         * All this might look a bit complex, but it can be maintained very
+         * small overhead and it gives very good statistics, based on which
+         * the scheduler can decide whether a task is 'interactive' or a
+         * 'CPU hog'. See sched.c for more details.
 	 */
-	struct list_head run_list;
-	unsigned long sleep_time;
+        #define SLEEP_HIST_SIZE 4
+ 
+        int hist_idx;
+        int hist[SLEEP_HIST_SIZE];
+ 
+        unsigned long policy;
+        unsigned long cpus_allowed;
 
 	struct task_struct *next_task, *prev_task;
-	struct mm_struct *active_mm;
+ 
+        struct mm_struct *mm, *active_mm;
+        struct list_head local_pages;
 
 /* task state */
 	struct linux_binfmt *binfmt;

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[khromy]

On Thu, Jan 10, 2002 at 07:43:04PM -0500, Ed Tomlinson wrote:
> Incase I messed up removing and repatch I tried from a clean kernel with the same results.
> Any one else seeing this?

Yes.. This is a PII350 with 128MiB... If anybody needs any more info let
me know.

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Dieter Nützel]

On Fri, Jan 11, 2002 at 00:52:16AM, khromy wrote:
> On Thu, Jan 10, 2002 at 07:43:04PM -0500, Ed Tomlinson wrote:
> > Incase I messed up removing and repatch I tried from a clean kernel with
> > the same results.
> > Any one else seeing this?
>
> Yes.. This is a PII350 with 128MiB... If anybody needs any more info let
> me know.

-H5 (-G1, latest I've tried worked)

1 GHz Athlon II, 640 MB 
hang hard right after
Initializing RT netlink socket

-- 
Dieter Nützel
Graduate Student, Computer Science

University of Hamburg
Department of Computer Science
@home: Dieter.Nuetzel@hamburg.de

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Robert Love]

On Thu, 2002-01-10 at 19:43, Ed Tomlinson wrote:

> The H4 sceduler does not boot here.  The G1 version worked.  The H4 version
> gets as far as:

It seems most people are having problems with the scheduler some time
after G1, at least in UP and 2.4.

Same problem: stops just prior or after 'Starting kswapd' ...

I'll see what changed ...

	Robert Love

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Davide Libenzi]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: TEXT/PLAIN; charset=X-UNKNOWN, Size: 615 bytes --]

On Fri, 11 Jan 2002, Dieter [iso-8859-15] Nützel wrote:

> On Fri, Jan 11, 2002 at 00:52:16AM, khromy wrote:
> > On Thu, Jan 10, 2002 at 07:43:04PM -0500, Ed Tomlinson wrote:
> > > Incase I messed up removing and repatch I tried from a clean kernel with
> > > the same results.
> > > Any one else seeing this?
> >
> > Yes.. This is a PII350 with 128MiB... If anybody needs any more info let
> > me know.
>
> -H5 (-G1, latest I've tried worked)
>
> 1 GHz Athlon II, 640 MB
> hang hard right after
> Initializing RT netlink socket

Look in init/main.c, if kernel_thread() is called before init_idle().




- Davide

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Robert Love]

On Thu, 2002-01-10 at 21:42, Davide Libenzi wrote:

> Look in init/main.c, if kernel_thread() is called before init_idle().

init is started via kernel_thread prior to init_idle ...

	Robert Love

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Davide Libenzi]

On 10 Jan 2002, Robert Love wrote:

> On Thu, 2002-01-10 at 21:42, Davide Libenzi wrote:
>
> > Look in init/main.c, if kernel_thread() is called before init_idle().
>
> init is started via kernel_thread prior to init_idle ...

Move init_idle() before the first call to kernel_thread().
This should fix it.



- Davide

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Robert Love]

On Thu, 2002-01-10 at 22:11, Davide Libenzi wrote:

> Move init_idle() before the first call to kernel_thread().
> This should fix it.

On 2.4.17-pre3, UP, with -H5, the following patch failed to fix the
problem -- still hardlock on "Starting kswapd".  I still suspect the
problem is with the init_idle changes, though ...

--- linux-2.4.18-pre3-ingo/init/main.c	Thu Jan 10 21:13:12 2002
+++ linux/init/main.c	Thu Jan 10 22:33:46 2002
@@ -590,14 +590,14 @@
 	check_bugs();
 	printk("POSIX conformance testing by UNIFIX\n");
 
+	smp_init();
+	init_idle();
 	kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL);
 	/* 
 	 *	We count on the initial thread going ok 
 	 *	Like idlers init is an unlocked kernel thread, which will
 	 *	make syscalls (and thus be locked).
 	 */
-	smp_init();
-	init_idle();
 	unlock_kernel();
 	printk("All processors have done init_idle\n");

	Robert Love

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Alex Davis]

I also tried 2.4.18pre3 with H5. The boot process hung in 
spawn_ksoftirqd at the kernel_thread call. 

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Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Taco IJsselmuiden]

> > > -H5 (-G1, latest I've tried worked)
> > >
> > > 1 GHz Athlon II, 640 MB
> > > hang hard right after
> > > Initializing RT netlink socket
> >
> > Look in init/main.c, if kernel_thread() is called before init_idle().
> 
> look at my patches, they have included this fix for quite some time.
> (Linus found it or me, i dont remember.) So whatever problem Dieter has,
> it's not this particular bug.

i've got the same problem (UP, athlon 500Mhz)
anything I can check/test ??

Cheers,
Taco.

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Ingo Molnar]

On Thu, 10 Jan 2002, Davide Libenzi wrote:

> > -H5 (-G1, latest I've tried worked)
> >
> > 1 GHz Athlon II, 640 MB
> > hang hard right after
> > Initializing RT netlink socket
>
> Look in init/main.c, if kernel_thread() is called before init_idle().

look at my patches, they have included this fix for quite some time.
(Linus found it or me, i dont remember.) So whatever problem Dieter has,
it's not this particular bug.

	Ingo

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Taco IJsselmuiden]

> quick question: your box is not SMP, correct? if it's a UP box then the
> softirq.c change probably makes no difference to the lockup.
OK, just booted (remote) with 2.5.2-pre11-H6 and it works !!!

haven't looked at the patch yet, but is sure fixed it for me ;)
let's hope the same goes for 2.4.x people...


Cheers,
Taco.

Re: [patch] O(1) scheduler, -H4 - 2.4.17 problems

[Robert Love]

On Fri, 2002-01-11 at 12:33, Taco IJsselmuiden wrote:

> OK, just booted (remote) with 2.5.2-pre11-H6 and it works !!!
> 
> haven't looked at the patch yet, but is sure fixed it for me ;)
> let's hope the same goes for 2.4.x people...

The problem is 2.4-only afaik.  That said, I think H6 fixed it, so good
luck.

	Robert Love