I noticed (and verified) that the relax_domain_level boot parameter does not
get processed because sched_domain_level_max is 0 at the time that
setup_relax_domain_level() is run.
int sched_domain_level_max;
static int __init setup_relax_domain_level(char *str)
{
unsigned long val;
val = simple_strtoul(str, NULL, 0);
if (val < sched_domain_level_max)
default_relax_domain_level = val;
return 1;
}
__setup("relax_domain_level=", setup_relax_domain_level);
struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
..
sched_domain_level_max = max(sched_domain_level_max, sd->level);
..
On Fri, 2012-06-01 at 16:03 -0500, Dimitri Sivanich wrote:
> I noticed (and verified) that the relax_domain_level boot parameter does not
> get processed because sched_domain_level_max is 0 at the time that
> setup_relax_domain_level() is run.
>
> int sched_domain_level_max;
>
> static int __init setup_relax_domain_level(char *str)
> {
> unsigned long val;
>
> val = simple_strtoul(str, NULL, 0);
> if (val < sched_domain_level_max)
> default_relax_domain_level = val;
>
> return 1;
> }
> __setup("relax_domain_level=", setup_relax_domain_level);
Ah indeed.. this has been so for a while I guess.
What are you using this knob for?
On Mon, Jun 04, 2012 at 05:37:42PM +0200, Peter Zijlstra wrote:
> On Fri, 2012-06-01 at 16:03 -0500, Dimitri Sivanich wrote:
> > I noticed (and verified) that the relax_domain_level boot parameter does not
> > get processed because sched_domain_level_max is 0 at the time that
> > setup_relax_domain_level() is run.
> >
> > int sched_domain_level_max;
> >
> > static int __init setup_relax_domain_level(char *str)
> > {
> > unsigned long val;
> >
> > val = simple_strtoul(str, NULL, 0);
> > if (val < sched_domain_level_max)
> > default_relax_domain_level = val;
> >
> > return 1;
> > }
> > __setup("relax_domain_level=", setup_relax_domain_level);
>
> Ah indeed.. this has been so for a while I guess.
On a very related note, the sched_relax_domain_level setting in cpuset
doesn't appear to work correctly either (if I'm interpreting all of this
correctly).
The reason is that the build_sched_domain() routine calls the
set_domain_attribute() routine prior to setting the sd->level, however,
the set_domain_attribute() routine relies on the sd->level to decide whether
idle load balancing will be off/on.
static void set_domain_attribute(struct sched_domain *sd,
..
==> if (request < sd->level) {
/* turn off idle balance on this domain */
..
..
struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
..
==> set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
==> sd->level = child->level + 1;
sched_domain_level_max = max(sched_domain_level_max, sd->level);
> What are you using this knob for?
I was poking around for different ways to turn off idle load balancing when
I ran into all of this.
On Mon, Jun 04, 2012 at 01:16:14PM -0500, Dimitri Sivanich wrote:
> On Mon, Jun 04, 2012 at 05:37:42PM +0200, Peter Zijlstra wrote:
> > On Fri, 2012-06-01 at 16:03 -0500, Dimitri Sivanich wrote:
> > > I noticed (and verified) that the relax_domain_level boot parameter does not
> > > get processed because sched_domain_level_max is 0 at the time that
> > > setup_relax_domain_level() is run.
> > >
> > > int sched_domain_level_max;
> > >
> > > static int __init setup_relax_domain_level(char *str)
> > > {
> > > unsigned long val;
> > >
> > > val = simple_strtoul(str, NULL, 0);
> > > if (val < sched_domain_level_max)
> > > default_relax_domain_level = val;
> > >
> > > return 1;
> > > }
> > > __setup("relax_domain_level=", setup_relax_domain_level);
> >
> > Ah indeed.. this has been so for a while I guess.
>
> On a very related note, the sched_relax_domain_level setting in cpuset
> doesn't appear to work correctly either (if I'm interpreting all of this
> correctly).
>
> The reason is that the build_sched_domain() routine calls the
> set_domain_attribute() routine prior to setting the sd->level, however,
> the set_domain_attribute() routine relies on the sd->level to decide whether
> idle load balancing will be off/on.
>
> static void set_domain_attribute(struct sched_domain *sd,
> ..
> ==> if (request < sd->level) {
> /* turn off idle balance on this domain */
> ..
> ..
> struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
> ..
> ==> set_domain_attribute(sd, attr);
> cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
> if (child) {
> ==> sd->level = child->level + 1;
> sched_domain_level_max = max(sched_domain_level_max, sd->level);
>
>
> > What are you using this knob for?
>
> I was poking around for different ways to turn off idle load balancing when
> I ran into all of this.
I'll submit a patch shortly that should return these back to what appears to
be their intended functionality.
On Tue, 2012-06-05 at 13:34 -0500, Dimitri Sivanich wrote:
>
> I'll submit a patch shortly that should return these back to what appears to
> be their intended functionality.
I guess removing the max check in the paramater parsing is the easiest
thing.
On Tue, Jun 05, 2012 at 08:36:59PM +0200, Peter Zijlstra wrote:
> On Tue, 2012-06-05 at 13:34 -0500, Dimitri Sivanich wrote:
> >
> > I'll submit a patch shortly that should return these back to what appears to
> > be their intended functionality.
>
> I guess removing the max check in the paramater parsing is the easiest
> thing.
My thoughts exactly.
Fix the relax_domain_level boot parameter. It does not get processed because
sched_domain_level_max is 0 at the time that setup_relax_domain_level()
is run. Simply accept the value as it is, as we don't know the value
of sched_domain_level_max until sched domain construction is completed.
Fix sched_relax_domain_level in cpuset. The build_sched_domain() routine calls
the set_domain_attribute() routine prior to setting the sd->level, however,
the set_domain_attribute() routine relies on the sd->level to decide whether
idle load balancing will be off/on.
Signed-off-by: Dimitri Sivanich <[email protected]>
---
kernel/sched/core.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
Index: linux/kernel/sched/core.c
===================================================================
--- linux.orig/kernel/sched/core.c
+++ linux/kernel/sched/core.c
@@ -6165,11 +6165,8 @@ int sched_domain_level_max;
static int __init setup_relax_domain_level(char *str)
{
- unsigned long val;
-
- val = simple_strtoul(str, NULL, 0);
- if (val < sched_domain_level_max)
- default_relax_domain_level = val;
+ if (kstrtoint(str, 0, &default_relax_domain_level))
+ pr_warn("Unable to set relax_domain_level\n");
return 1;
}
@@ -6543,7 +6540,6 @@ struct sched_domain *build_sched_domain(
if (!sd)
return child;
- set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
sd->level = child->level + 1;
@@ -6551,6 +6547,7 @@ struct sched_domain *build_sched_domain(
child->parent = sd;
}
sd->child = child;
+ set_domain_attribute(sd, attr);
return sd;
}
Commit-ID: a841f8cef4bb124f0f5563314d0beaf2e1249d72
Gitweb: http://git.kernel.org/tip/a841f8cef4bb124f0f5563314d0beaf2e1249d72
Author: Dimitri Sivanich <[email protected]>
AuthorDate: Tue, 5 Jun 2012 13:44:36 -0500
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 6 Jun 2012 17:07:41 +0200
sched: Fix the relax_domain_level boot parameter
It does not get processed because sched_domain_level_max is 0 at the
time that setup_relax_domain_level() is run.
Simply accept the value as it is, as we don't know the value of
sched_domain_level_max until sched domain construction is completed.
Fix sched_relax_domain_level in cpuset. The build_sched_domain() routine calls
the set_domain_attribute() routine prior to setting the sd->level, however,
the set_domain_attribute() routine relies on the sd->level to decide whether
idle load balancing will be off/on.
Signed-off-by: Dimitri Sivanich <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/core.c | 9 +++------
1 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2bdd176..d5594a4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6268,11 +6268,8 @@ int sched_domain_level_max;
static int __init setup_relax_domain_level(char *str)
{
- unsigned long val;
-
- val = simple_strtoul(str, NULL, 0);
- if (val < sched_domain_level_max)
- default_relax_domain_level = val;
+ if (kstrtoint(str, 0, &default_relax_domain_level))
+ pr_warn("Unable to set relax_domain_level\n");
return 1;
}
@@ -6698,7 +6695,6 @@ struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
if (!sd)
return child;
- set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
sd->level = child->level + 1;
@@ -6706,6 +6702,7 @@ struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
child->parent = sd;
}
sd->child = child;
+ set_domain_attribute(sd, attr);
return sd;
}