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| Started by | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| First post | 2015-08-07 00:20 +0200 |
| Last post | 2015-08-09 02:10 +0200 |
| Articles | 8 — 2 participants |
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[PATCH RT 0/6] Linux 3.14.48-rt49-rc1 Steven Rostedt <rostedt@goodmis.org> - 2015-08-07 00:20 +0200
[PATCH RT 5/6] powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT_FULL Steven Rostedt <rostedt@goodmis.org> - 2015-08-07 00:20 +0200
[PATCH RT 6/6] Linux 3.14.48-rt49-rc1 Steven Rostedt <rostedt@goodmis.org> - 2015-08-07 00:30 +0200
[PATCH RT 2/6] mm/slub: move slab initialization into irq enabled region Steven Rostedt <rostedt@goodmis.org> - 2015-08-07 00:30 +0200
[PATCH RT 1/6] Revert "slub: delay ctor until the object is requested" Steven Rostedt <rostedt@goodmis.org> - 2015-08-07 00:30 +0200
Re: [PATCH RT 0/6] Linux 3.14.48-rt49-rc1 Paul Gortmaker <paul.gortmaker@windriver.com> - 2015-08-09 01:20 +0200
Re: [PATCH RT 0/6] Linux 3.14.48-rt49-rc1 Steven Rostedt <rostedt@goodmis.org> - 2015-08-09 01:30 +0200
Re: [PATCH RT 0/6] Linux 3.14.48-rt49-rc1 Paul Gortmaker <paul.gortmaker@windriver.com> - 2015-08-09 02:10 +0200
| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-07 00:20 +0200 |
| Subject | [PATCH RT 0/6] Linux 3.14.48-rt49-rc1 |
| Message-ID | <pUBG1-5pj-5@gated-at.bofh.it> |
Dear RT Folks,
This is the RT stable review cycle of patch 3.14.48-rt49-rc1.
Please scream at me if I messed something up. Please test the patches too.
The -rc release will be uploaded to kernel.org and will be deleted when
the final release is out. This is just a review release (or release candidate).
The pre-releases will not be pushed to the git repository, only the
final release is.
If all goes well, this patch will be converted to the next main release
on 8/10/2015.
Note, these changes appear to make NO_HZ_FULL work as well as 3.18-rt does.
Enjoy,
-- Steve
To build 3.14.48-rt49-rc1 directly, the following patches should be applied:
http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.14.tar.xz
http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.14.48.xz
http://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patch-3.14.48-rt49-rc1.patch.xz
You can also build from 3.14.48-rt48 by applying the incremental patch:
http://www.kernel.org/pub/linux/kernel/projects/rt/3.14/incr/patch-3.14.48-rt48-rt49-rc1.patch.xz
Changes from 3.14.48-rt48:
---
Bogdan Purcareata (1):
powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT_FULL
Frederic Weisbecker (1):
x86-Tell-irq-work-about-self-IPI-support-3.14
Sebastian Andrzej Siewior (1):
Revert "slub: delay ctor until the object is requested"
Steven Rostedt (1):
xfs: Disable percpu SB on PREEMPT_RT_FULL
Steven Rostedt (Red Hat) (1):
Linux 3.14.48-rt49-rc1
Thomas Gleixner (1):
mm/slub: move slab initialization into irq enabled region
----
arch/powerpc/kvm/Kconfig | 1 +
arch/x86/include/asm/Kbuild | 1 -
arch/x86/include/asm/irq_work.h | 11 ++++++
arch/x86/kernel/irq_work.c | 2 +-
fs/xfs/xfs_linux.h | 2 +-
localversion-rt | 2 +-
mm/slub.c | 86 +++++++++++++++++++----------------------
7 files changed, 54 insertions(+), 51 deletions(-)
create mode 100644 arch/x86/include/asm/irq_work.h
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-07 00:20 +0200 |
| Subject | [PATCH RT 5/6] powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT_FULL |
| Message-ID | <pUBG1-5pj-13@gated-at.bofh.it> |
| In reply to | #1202118 |
3.14.48-rt49-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Bogdan Purcareata <bogdan.purcareata@freescale.com> While converting the openpic emulation code to use a raw_spinlock_t enables guests to run on RT, there's still a performance issue. For interrupts sent in directed delivery mode with a multiple CPU mask, the emulated openpic will loop through all of the VCPUs, and for each VCPUs, it call IRQ_check, which will loop through all the pending interrupts for that VCPU. This is done while holding the raw_lock, meaning that in all this time the interrupts and preemption are disabled on the host Linux. A malicious user app can max both these number and cause a DoS. This temporary fix is sent for two reasons. First is so that users who want to use the in-kernel MPIC emulation are aware of the potential latencies, thus making sure that the hardware MPIC and their usage scenario does not involve interrupts sent in directed delivery mode, and the number of possible pending interrupts is kept small. Secondly, this should incentivize the development of a proper openpic emulation that would be better suited for RT. Cc: stable-rt@vger.kernel.org Acked-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- arch/powerpc/kvm/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index 141b2027189a..a0258b2b0f72 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -172,6 +172,7 @@ config KVM_E500MC config KVM_MPIC bool "KVM in-kernel MPIC emulation" depends on KVM && E500 + depends on !PREEMPT_RT_FULL select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQ_ROUTING select HAVE_KVM_MSI -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-07 00:30 +0200 |
| Subject | [PATCH RT 6/6] Linux 3.14.48-rt49-rc1 |
| Message-ID | <pUBPH-5As-7@gated-at.bofh.it> |
| In reply to | #1202118 |
3.14.48-rt49-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> --- localversion-rt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/localversion-rt b/localversion-rt index 24707986c321..623b4c9cb701 100644 --- a/localversion-rt +++ b/localversion-rt @@ -1 +1 @@ --rt48 +-rt49-rc1 -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-07 00:30 +0200 |
| Subject | [PATCH RT 2/6] mm/slub: move slab initialization into irq enabled region |
| Message-ID | <pUBPH-5As-9@gated-at.bofh.it> |
| In reply to | #1202118 |
3.14.48-rt49-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <tglx@linutronix.de>
Initializing a new slab can introduce rather large latencies because most
of the initialization runs always with interrupts disabled.
There is no point in doing so. The newly allocated slab is not visible
yet, so there is no reason to protect it against concurrent alloc/free.
Move the expensive parts of the initialization into allocate_slab(), so
for all allocations with GFP_WAIT set, interrupts are enabled.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
mm/slub.c | 80 +++++++++++++++++++++++++++++++--------------------------------
1 file changed, 39 insertions(+), 41 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 5b0e9ee52f79..f21e9bcb9094 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1316,6 +1316,14 @@ struct slub_free_list {
};
static DEFINE_PER_CPU(struct slub_free_list, slub_free_list);
+static void setup_object(struct kmem_cache *s, struct page *page,
+ void *object)
+{
+ setup_object_debug(s, page, object);
+ if (unlikely(s->ctor))
+ s->ctor(object);
+}
+
/*
* Slab allocation and freeing
*/
@@ -1338,6 +1346,8 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
struct kmem_cache_order_objects oo = s->oo;
gfp_t alloc_gfp;
bool enableirqs;
+ void *start, *last, *p;
+ int idx, order;
flags &= gfp_allowed_mask;
@@ -1364,13 +1374,13 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
* Try a lower order alloc if possible
*/
page = alloc_slab_page(flags, node, oo);
-
- if (page)
- stat(s, ORDER_FALLBACK);
+ if (unlikely(!page))
+ goto out;
+ stat(s, ORDER_FALLBACK);
}
- if (kmemcheck_enabled && page
- && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
+ if (kmemcheck_enabled &&
+ !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
int pages = 1 << oo_order(oo);
kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
@@ -1385,45 +1395,9 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
kmemcheck_mark_unallocated_pages(page, pages);
}
- if (enableirqs)
- local_irq_disable();
- if (!page)
- return NULL;
-
page->objects = oo_objects(oo);
- mod_zone_page_state(page_zone(page),
- (s->flags & SLAB_RECLAIM_ACCOUNT) ?
- NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
- 1 << oo_order(oo));
-
- return page;
-}
-
-static void setup_object(struct kmem_cache *s, struct page *page,
- void *object)
-{
- setup_object_debug(s, page, object);
- if (unlikely(s->ctor))
- s->ctor(object);
-}
-
-static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
-{
- struct page *page;
- void *start;
- void *last;
- void *p;
- int order;
-
- BUG_ON(flags & GFP_SLAB_BUG_MASK);
-
- page = allocate_slab(s,
- flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
- if (!page)
- goto out;
order = compound_order(page);
- inc_slabs_node(s, page_to_nid(page), page->objects);
memcg_bind_pages(s, order);
page->slab_cache = s;
__SetPageSlab(page);
@@ -1447,10 +1421,34 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
page->freelist = start;
page->inuse = page->objects;
page->frozen = 1;
+
out:
+ if (enableirqs)
+ local_irq_disable();
+ if (!page)
+ return NULL;
+
+ mod_zone_page_state(page_zone(page),
+ (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+ NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
+ 1 << oo_order(oo));
+
+ inc_slabs_node(s, page_to_nid(page), page->objects);
+
return page;
}
+static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
+ pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
+ BUG();
+ }
+
+ return allocate_slab(s,
+ flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
+}
+
static void __free_slab(struct kmem_cache *s, struct page *page)
{
int order = compound_order(page);
--
2.1.4
--
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-07 00:30 +0200 |
| Subject | [PATCH RT 1/6] Revert "slub: delay ctor until the object is requested" |
| Message-ID | <pUBPH-5As-11@gated-at.bofh.it> |
| In reply to | #1202118 |
3.14.48-rt49-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
This approach is broken with SLAB_DESTROY_BY_RCU allocations.
Reported by Steven Rostedt and Koehrer Mathias.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
mm/slub.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 93eeaca6cb53..5b0e9ee52f79 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1403,10 +1403,8 @@ static void setup_object(struct kmem_cache *s, struct page *page,
void *object)
{
setup_object_debug(s, page, object);
-#ifndef CONFIG_PREEMPT_RT_FULL
if (unlikely(s->ctor))
s->ctor(object);
-#endif
}
static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
@@ -2519,10 +2517,6 @@ redo:
if (unlikely(gfpflags & __GFP_ZERO) && object)
memset(object, 0, s->object_size);
-#ifdef CONFIG_PREEMPT_RT_FULL
- if (unlikely(s->ctor) && object)
- s->ctor(object);
-#endif
slab_post_alloc_hook(s, gfpflags, object);
--
2.1.4
--
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| From | Paul Gortmaker <paul.gortmaker@windriver.com> |
|---|---|
| Date | 2015-08-09 01:20 +0200 |
| Message-ID | <pVlzb-4RX-1@gated-at.bofh.it> |
| In reply to | #1202118 |
[[PATCH RT 0/6] Linux 3.14.48-rt49-rc1] On 06/08/2015 (Thu 18:17) Steven Rostedt wrote:
>
> Dear RT Folks,
>
> This is the RT stable review cycle of patch 3.14.48-rt49-rc1.
>
> Please scream at me if I messed something up. Please test the patches too.
>
> The -rc release will be uploaded to kernel.org and will be deleted when
> the final release is out. This is just a review release (or release candidate).
>
> The pre-releases will not be pushed to the git repository, only the
> final release is.
>
> If all goes well, this patch will be converted to the next main release
> on 8/10/2015.
>
> Note, these changes appear to make NO_HZ_FULL work as well as 3.18-rt does.
Appears to pass a simple sanity test here as well. Built basically a
defconfig + RT_FULL + NOHZ_FULL + FHANDLE + DEVTMPFS and ran this simple
test "t" -- meant to test 1st NOHZ and then NOHZ_FULL (loaded core).
Bootargs (below) and irqaffine and rcu-affine scripts (also below) are
meant to dump all housekeeping crap onto core zero.
---------------------------------------
root@testbox:/home/paul# cat t
cat /proc/interrupts |grep LOC
sleep 5
cat /proc/interrupts |grep LOC
taskset -c 5 ./eatme &
sleep 5
cat /proc/interrupts |grep LOC
kill %
root@testbox:/home/paul# ./t
LOC: 220787 1635 1614 1597 1579 1563 1543 1529 1512 1492 1414 1392 1375 1360 1342 1327 1307 1290 1277 1260 Local timer interrupts
LOC: 225795 1637 1616 1597 1579 1563 1543 1529 1512 1492 1414 1392 1375 1362 1345 1329 1310 1293 1279 1262 Local timer interrupts
LOC: 230800 1637 1616 1599 1582 1583 1545 1532 1514 1494 1416 1394 1377 1362 1345 1329 1310 1293 1279 1262 Local timer interrupts
root@testbox:/home/paul# jobs
root@testbox:/home/paul# cat /proc/version
Linux version 3.14.48-rt49-rc1-00071-g3fdc6bccf1b7 (paul@yow-dellw-pg2) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #1 SMP PREEMPT RT Sat Aug 8 15:08:25 EDT 2015
root@testbox:/home/paul# cat /proc/cmdline
root=/dev/sda2 ro console=ttyS0,115200 isolcpus=1-20 rcu_nocbs=1-20 rcu_nocb_poll nohz_full=1-20 irqaffinity=0 idle=poll tsc=perfect
root@testbox:/home/paul# cat no-rcu
for i in `pgrep rcuo` ; do taskset -c -p 0 $i ; done
root@testbox:/home/paul# cat clear-core
#!/bin/bash
# for all interrupting devices; move them to core zero; assumes that
for i in `cat /proc/interrupts | grep '^ *[0-9]*[0-9]:' |awk {'print $1}'|sed 's/:$//' `; do
# Timer
if [ "$i" = "0" ]; then
continue
fi
# cascade
if [ "$i" = "2" ]; then
continue
fi
echo setting $i to affine for core zero
echo 1 > /proc/irq/$i/smp_affinity
done
root@testbox:/home/paul#
---------------------------------------
So we took 20 IRQs in 5s, or 4/s ; not quite the 1/s minimum, but definitely not
the HZ/s we'd get w/o NOHZ_FULL. Re-running it got consistently 18-20 IRQ / 5s.
I specifically did NOT unplug and replug cores to "clean" them of tasks; the
hotplug code just seems to unstable for that from what I've seen in the past,
and by the looks of the irq counts above, there was no need to either.
The rootfs was basically a ubu 14.10 server install (no X11/gfx) -- not that
it should matter - so long as other tasks weren't running on the nohz cores.
Paul.
--
>
> Enjoy,
>
> -- Steve
>
--
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| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Date | 2015-08-09 01:30 +0200 |
| Message-ID | <pVlIR-539-5@gated-at.bofh.it> |
| In reply to | #1203552 |
On Sat, 8 Aug 2015 19:10:17 -0400 Paul Gortmaker <paul.gortmaker@windriver.com> wrote: > So we took 20 IRQs in 5s, or 4/s ; not quite the 1/s minimum, but definitely not > the HZ/s we'd get w/o NOHZ_FULL. Re-running it got consistently 18-20 IRQ / 5s. OK, so NO_HZ_FULL still isn't great on -rt, but this shows that it keeps disturbances much lower than without it. Thanks for the report! -- Steve > > I specifically did NOT unplug and replug cores to "clean" them of tasks; the > hotplug code just seems to unstable for that from what I've seen in the past, > and by the looks of the irq counts above, there was no need to either. > > The rootfs was basically a ubu 14.10 server install (no X11/gfx) -- not that > it should matter - so long as other tasks weren't running on the nohz cores. > > Paul. > -- > > > > > Enjoy, > > > > -- Steve > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Paul Gortmaker <paul.gortmaker@windriver.com> |
|---|---|
| Date | 2015-08-09 02:10 +0200 |
| Message-ID | <pVmlA-61H-3@gated-at.bofh.it> |
| In reply to | #1203553 |
[Re: [PATCH RT 0/6] Linux 3.14.48-rt49-rc1] On 08/08/2015 (Sat 19:23) Steven Rostedt wrote:
> On Sat, 8 Aug 2015 19:10:17 -0400
> Paul Gortmaker <paul.gortmaker@windriver.com> wrote:
>
>
> > So we took 20 IRQs in 5s, or 4/s ; not quite the 1/s minimum, but definitely not
> > the HZ/s we'd get w/o NOHZ_FULL. Re-running it got consistently 18-20 IRQ / 5s.
>
> OK, so NO_HZ_FULL still isn't great on -rt, but this shows that it
> keeps disturbances much lower than without it.
Here is several runs on vanilla ("make oldconfig" of the -rt .config)
and all else (bootargs, isolation, rcu offload) the same:
--------------------------------------------------
root@testbox:/home/paul# ./t
LOC: 86341 740 724 708 694 679 663 649 633 619 545 526 512 494 481 463 448 434 420 404 Local timer interrupts
LOC: 91349 742 727 708 694 679 663 649 633 619 545 526 512 496 483 465 450 436 423 406 Local timer interrupts
LOC: 96353 742 727 710 697 709 665 651 635 622 547 528 514 496 483 465 450 436 423 406 Local timer interrupts
root@testbox:/home/paul# ./t
LOC: 106188 744 729 712 699 711 667 653 638 624 549 530 514 498 485 467 452 438 425 408 Local timer interrupts
LOC: 111194 746 729 712 699 711 667 653 638 624 549 530 516 500 487 469 454 440 427 410 Local timer interrupts
LOC: 116199 746 731 714 701 729 669 655 640 626 551 532 516 500 487 469 454 440 427 410 Local timer interrupts
root@testbox:/home/paul# ./t
LOC: 122860 748 733 716 703 731 669 655 640 626 551 532 518 502 489 471 456 442 429 412 Local timer interrupts
LOC: 127866 748 733 716 703 731 671 657 642 628 553 534 520 504 492 473 456 442 429 412 Local timer interrupts
LOC: 132872 750 735 718 706 748 671 657 642 628 553 534 520 504 492 473 458 444 431 415 Local timer interrupts
root@testbox:/home/paul# cat /proc/version
Linux version 3.14.48 (paul@yow-dellw-pg2) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #2 SMP PREEMPT Sat Aug 8 19:52:12 EDT 2015
root@testbox:/home/paul#
--------------------------------------------------
So 30, 18, and 17 per 5s interval. I'd say that is statisitcally close
enough to -rt on this simple test to call -rt on par with vanilla.
Things might show a difference with more complicated tests, more cores
doing real work etc etc. -- this really is just a simple sanity test
though... but at least it is a test that we now can pass!
Paul.
--
>
> Thanks for the report!
>
> -- Steve
>
> >
> > I specifically did NOT unplug and replug cores to "clean" them of tasks; the
> > hotplug code just seems to unstable for that from what I've seen in the past,
> > and by the looks of the irq counts above, there was no need to either.
> >
> > The rootfs was basically a ubu 14.10 server install (no X11/gfx) -- not that
> > it should matter - so long as other tasks weren't running on the nohz cores.
> >
> > Paul.
> > --
> >
> > >
> > > Enjoy,
> > >
> > > -- Steve
> > >
>
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