* [PATCH] x86 uv: lower UV rtc clocksource rating
@ 2012-02-16 20:10 Dimitri Sivanich
2012-02-17 12:02 ` Ingo Molnar
0 siblings, 1 reply; 5+ messages in thread
From: Dimitri Sivanich @ 2012-02-16 20:10 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, John Stultz
Cc: x86, linux-kernel, Jack Steiner
Lower the rating of the UV rtc clocksource to just below that of the tsc.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
---
arch/x86/platform/uv/uv_time.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
Index: linux/arch/x86/platform/uv/uv_time.c
===================================================================
--- linux.orig/arch/x86/platform/uv/uv_time.c
+++ linux/arch/x86/platform/uv/uv_time.c
@@ -37,7 +37,7 @@ static void uv_rtc_timer_setup(enum cloc
static struct clocksource clocksource_uv = {
.name = RTC_NAME,
- .rating = 400,
+ .rating = 299,
.read = uv_read_rtc,
.mask = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
@@ -379,10 +379,6 @@ static __init int uv_rtc_setup_clock(voi
if (!is_uv_system())
return -ENODEV;
- /* If single blade, prefer tsc */
- if (uv_num_possible_blades() == 1)
- clocksource_uv.rating = 250;
-
rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
if (rc)
printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86 uv: lower UV rtc clocksource rating
2012-02-16 20:10 [PATCH] x86 uv: lower UV rtc clocksource rating Dimitri Sivanich
@ 2012-02-17 12:02 ` Ingo Molnar
2012-02-17 14:16 ` Dimitri Sivanich
0 siblings, 1 reply; 5+ messages in thread
From: Ingo Molnar @ 2012-02-17 12:02 UTC (permalink / raw)
To: Dimitri Sivanich
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, John Stultz, x86,
linux-kernel, Jack Steiner
* Dimitri Sivanich <sivanich@sgi.com> wrote:
> Lower the rating of the UV rtc clocksource to just below that of the tsc.
This changelog is deficient for obvious reasons, mind updating
it?
Thanks,
Ingo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86 uv: lower UV rtc clocksource rating
2012-02-17 12:02 ` Ingo Molnar
@ 2012-02-17 14:16 ` Dimitri Sivanich
2012-02-19 12:51 ` Ingo Molnar
2012-02-20 11:46 ` [tip:x86/uv] x86/UV: Lower " tip-bot for Dimitri Sivanich
0 siblings, 2 replies; 5+ messages in thread
From: Dimitri Sivanich @ 2012-02-17 14:16 UTC (permalink / raw)
To: Ingo Molnar
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, John Stultz, x86,
linux-kernel, Jack Steiner
On Fri, Feb 17, 2012 at 01:02:42PM +0100, Ingo Molnar wrote:
>
> * Dimitri Sivanich <sivanich@sgi.com> wrote:
>
> > Lower the rating of the UV rtc clocksource to just below that of the tsc.
>
> This changelog is deficient for obvious reasons, mind updating
> it?
>
OK. Is this sufficient?
Lower the rating of the UV rtc clocksource to just below that of the tsc.
Reading the tsc clocksource has lower latency than reading the rtc, so favor
it in situations where it is synchronized and stable. When the tsc is
unsynchronized, the rtc needs to be the chosen clocksource.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
---
arch/x86/platform/uv/uv_time.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
Index: linux/arch/x86/platform/uv/uv_time.c
===================================================================
--- linux.orig/arch/x86/platform/uv/uv_time.c
+++ linux/arch/x86/platform/uv/uv_time.c
@@ -37,7 +37,7 @@ static void uv_rtc_timer_setup(enum cloc
static struct clocksource clocksource_uv = {
.name = RTC_NAME,
- .rating = 400,
+ .rating = 299,
.read = uv_read_rtc,
.mask = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
@@ -379,10 +379,6 @@ static __init int uv_rtc_setup_clock(voi
if (!is_uv_system())
return -ENODEV;
- /* If single blade, prefer tsc */
- if (uv_num_possible_blades() == 1)
- clocksource_uv.rating = 250;
-
rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
if (rc)
printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86 uv: lower UV rtc clocksource rating
2012-02-17 14:16 ` Dimitri Sivanich
@ 2012-02-19 12:51 ` Ingo Molnar
2012-02-20 11:46 ` [tip:x86/uv] x86/UV: Lower " tip-bot for Dimitri Sivanich
1 sibling, 0 replies; 5+ messages in thread
From: Ingo Molnar @ 2012-02-19 12:51 UTC (permalink / raw)
To: Dimitri Sivanich
Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin, John Stultz, x86,
linux-kernel, Jack Steiner
* Dimitri Sivanich <sivanich@sgi.com> wrote:
> On Fri, Feb 17, 2012 at 01:02:42PM +0100, Ingo Molnar wrote:
> >
> > * Dimitri Sivanich <sivanich@sgi.com> wrote:
> >
> > > Lower the rating of the UV rtc clocksource to just below that of the tsc.
> >
> > This changelog is deficient for obvious reasons, mind updating
> > it?
> >
> OK. Is this sufficient?
>
>
> Lower the rating of the UV rtc clocksource to just below that of the tsc.
>
> Reading the tsc clocksource has lower latency than reading the rtc, so favor
> it in situations where it is synchronized and stable. When the tsc is
> unsynchronized, the rtc needs to be the chosen clocksource.
Yeah, perfect, thanks.
Ingo
^ permalink raw reply [flat|nested] 5+ messages in thread
* [tip:x86/uv] x86/UV: Lower UV rtc clocksource rating
2012-02-17 14:16 ` Dimitri Sivanich
2012-02-19 12:51 ` Ingo Molnar
@ 2012-02-20 11:46 ` tip-bot for Dimitri Sivanich
1 sibling, 0 replies; 5+ messages in thread
From: tip-bot for Dimitri Sivanich @ 2012-02-20 11:46 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, steiner, johnstul, tglx, sivanich, mingo
Commit-ID: b0deca2e0270135f797e81bdb0743e50fd1dc58d
Gitweb: http://git.kernel.org/tip/b0deca2e0270135f797e81bdb0743e50fd1dc58d
Author: Dimitri Sivanich <sivanich@sgi.com>
AuthorDate: Fri, 17 Feb 2012 08:16:41 -0600
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 20 Feb 2012 09:07:56 +0100
x86/UV: Lower UV rtc clocksource rating
Lower the rating of the UV rtc clocksource to just below that of
the tsc, to improve performance.
Reading the tsc clocksource has lower latency than reading the
rtc, so favor it in situations where it is synchronized and
stable. When the tsc is unsynchronized, the rtc needs to be the
chosen clocksource.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/20120217141641.GA28063@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/platform/uv/uv_time.c | 6 +-----
1 files changed, 1 insertions(+), 5 deletions(-)
diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c
index 9f29a01..5032e0d 100644
--- a/arch/x86/platform/uv/uv_time.c
+++ b/arch/x86/platform/uv/uv_time.c
@@ -37,7 +37,7 @@ static void uv_rtc_timer_setup(enum clock_event_mode,
static struct clocksource clocksource_uv = {
.name = RTC_NAME,
- .rating = 400,
+ .rating = 299,
.read = uv_read_rtc,
.mask = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
@@ -379,10 +379,6 @@ static __init int uv_rtc_setup_clock(void)
if (!is_uv_system())
return -ENODEV;
- /* If single blade, prefer tsc */
- if (uv_num_possible_blades() == 1)
- clocksource_uv.rating = 250;
-
rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
if (rc)
printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-02-20 11:47 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2012-02-16 20:10 [PATCH] x86 uv: lower UV rtc clocksource rating Dimitri Sivanich
2012-02-17 12:02 ` Ingo Molnar
2012-02-17 14:16 ` Dimitri Sivanich
2012-02-19 12:51 ` Ingo Molnar
2012-02-20 11:46 ` [tip:x86/uv] x86/UV: Lower " tip-bot for Dimitri Sivanich
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