Re: [PATCH 0/5] cpuidle-pseries: Parse extended CEDE information for idle.
Hello Rafael, On Mon, Jul 27, 2020 at 04:14:12PM +0200, Rafael J. Wysocki wrote: > On Tue, Jul 7, 2020 at 1:32 PM Gautham R Shenoy > wrote: > > > > Hi, > > > > On Tue, Jul 07, 2020 at 04:41:34PM +0530, Gautham R. Shenoy wrote: > > > From: "Gautham R. Shenoy" > > > > > > Hi, > > > > > > > > > > > > > > > Gautham R. Shenoy (5): > > > cpuidle-pseries: Set the latency-hint before entering CEDE > > > cpuidle-pseries: Add function to parse extended CEDE records > > > cpuidle-pseries : Fixup exit latency for CEDE(0) > > > cpuidle-pseries : Include extended CEDE states in cpuidle framework > > > cpuidle-pseries: Block Extended CEDE(1) which adds no additional > > > value. > > > > Forgot to mention that these patches are on top of Nathan's series to > > remove extended CEDE offline and bogus topology update code : > > https://lore.kernel.org/linuxppc-dev/20200612051238.1007764-1-nath...@linux.ibm.com/ > > OK, so this is targeted at the powerpc maintainers, isn't it? Yes, the code is powerpc specific. Also, I noticed that Nathan's patches have been merged by Michael Ellerman in the powerpc/merge tree. I will rebase and post a v2 of this patch series. -- Thanks and Regards gautham.
Re: [PATCH 0/5] cpuidle-pseries: Parse extended CEDE information for idle.
On Tue, Jul 7, 2020 at 1:32 PM Gautham R Shenoy wrote: > > Hi, > > On Tue, Jul 07, 2020 at 04:41:34PM +0530, Gautham R. Shenoy wrote: > > From: "Gautham R. Shenoy" > > > > Hi, > > > > > > > > > > Gautham R. Shenoy (5): > > cpuidle-pseries: Set the latency-hint before entering CEDE > > cpuidle-pseries: Add function to parse extended CEDE records > > cpuidle-pseries : Fixup exit latency for CEDE(0) > > cpuidle-pseries : Include extended CEDE states in cpuidle framework > > cpuidle-pseries: Block Extended CEDE(1) which adds no additional > > value. > > Forgot to mention that these patches are on top of Nathan's series to > remove extended CEDE offline and bogus topology update code : > https://lore.kernel.org/linuxppc-dev/20200612051238.1007764-1-nath...@linux.ibm.com/ OK, so this is targeted at the powerpc maintainers, isn't it?
Re: [PATCH 0/5] cpuidle-pseries: Parse extended CEDE information for idle.
* Gautham R Shenoy [2020-07-07 16:41:34]:
> From: "Gautham R. Shenoy"
>
> Hi,
>
> On pseries Dedicated Linux LPARs, apart from the polling snooze idle
> state, we currently have the CEDE idle state which cedes the CPU to
> the hypervisor with latency-hint = 0.
>
> However, the PowerVM hypervisor supports additional extended CEDE
> states, which can be queried through the "ibm,get-systems-parameter"
> rtas-call with the CEDE_LATENCY_TOKEN. The hypervisor maps these
> extended CEDE states to appropriate platform idle-states in order to
> provide energy-savings as well as shifting power to the active
> units. On existing pseries LPARs today we have extended CEDE with
> latency-hints {1,2} supported.
>
> In Patches 1-3 of this patchset, we add the code to parse the CEDE
> latency records provided by the hypervisor. We use this information to
> determine the wakeup latency of the regular CEDE (which we have been
> so far hardcoding to 10us while experimentally it is much lesser ~
> 1us), by looking at the wakeup latency provided by the hypervisor for
> Extended CEDE states. Since the platform currently advertises Extended
> CEDE 1 to have wakeup latency of 2us, we can be sure that the wakeup
> latency of the regular CEDE is no more than this.
>
> Patch 4 (currently marked as RFC), expose the extended CEDE states
> parsed above to the cpuidle framework, provided that they can wakeup
> on an interrupt. On current platforms only Extended CEDE 1 fits the
> bill, but this is going to change in future platforms where even
> Extended CEDE 2 may be responsive to external interrupts.
>
> Patch 5 (currently marked as RFC), filters out Extended CEDE 1 since
> it offers no added advantage over the normal CEDE.
>
> With Patches 1-3, we see an improvement in the single-threaded
> performance on ebizzy.
>
> 2 ebizzy threads bound to the same big-core. 25% improvement in the
> avg records/s (higher the better) with patches 1-3.
> x without_patches
> * with_patches
> N Min MaxMedian AvgStddev
> x 10 2491089 5834307 5398375 4244335 1596244.9
> * 10 2893813 5834474 5832448 5327281.3 1055941.4
>
> We do not observe any major regression in either the context_switch2
> benchmark or the schbench benchmark
>
> context_switch2 across CPU0 CPU1 (Both belong to same big-core, but different
> small cores). We observe a minor 0.14% regression in the number of
> context-switches (higher is better).
> x without_patch
> * with_patch
> N Min MaxMedian AvgStddev
> x 500348872362236354712 354745.69 2711.827
> * 500349422361452353942 354215.4 2576.9258
>
> context_switch2 across CPU0 CPU8 (Different big-cores). We observe a 0.37%
> improvement in the number of context-switches (higher is better).
> x without_patch
> * with_patch
> N Min MaxMedian AvgStddev
> x 500287956294940288896 288977.23 646.59295
> * 500288300294646289582 290064.76 1161.9992
>
> schbench:
> No major difference could be seen until the 99.9th percentile.
>
> Without-patch
> Latency percentiles (usec)
> 50.0th: 29
> 75.0th: 39
> 90.0th: 49
> 95.0th: 59
> *99.0th: 13104
> 99.5th: 14672
> 99.9th: 15824
> min=0, max=17993
>
> With-patch:
> Latency percentiles (usec)
> 50.0th: 29
> 75.0th: 40
> 90.0th: 50
> 95.0th: 61
> *99.0th: 13648
> 99.5th: 14768
> 99.9th: 15664
> min=0, max=29812
This patch series mainly cleans up the CEDE latency discovery and
prepares to add different cpuidle states in virtualised environment.
This helps in improving SMT folding speeds and also power savings and
power shifting with newer platform firmware.
The current benefit is primarily from faster SMT folding and resulting
single performance achieved by updating the platform firmware provided
heuristics in the cpuidle states.
--Vaidy
Re: [PATCH 0/5] cpuidle-pseries: Parse extended CEDE information for idle.
Hi, On Tue, Jul 07, 2020 at 04:41:34PM +0530, Gautham R. Shenoy wrote: > From: "Gautham R. Shenoy" > > Hi, > > > > > Gautham R. Shenoy (5): > cpuidle-pseries: Set the latency-hint before entering CEDE > cpuidle-pseries: Add function to parse extended CEDE records > cpuidle-pseries : Fixup exit latency for CEDE(0) > cpuidle-pseries : Include extended CEDE states in cpuidle framework > cpuidle-pseries: Block Extended CEDE(1) which adds no additional > value. Forgot to mention that these patches are on top of Nathan's series to remove extended CEDE offline and bogus topology update code : https://lore.kernel.org/linuxppc-dev/20200612051238.1007764-1-nath...@linux.ibm.com/ > > drivers/cpuidle/cpuidle-pseries.c | 268 > +- > 1 file changed, 266 insertions(+), 2 deletions(-) > > -- > 1.9.4 >
[PATCH 0/5] cpuidle-pseries: Parse extended CEDE information for idle.
From: "Gautham R. Shenoy"
Hi,
On pseries Dedicated Linux LPARs, apart from the polling snooze idle
state, we currently have the CEDE idle state which cedes the CPU to
the hypervisor with latency-hint = 0.
However, the PowerVM hypervisor supports additional extended CEDE
states, which can be queried through the "ibm,get-systems-parameter"
rtas-call with the CEDE_LATENCY_TOKEN. The hypervisor maps these
extended CEDE states to appropriate platform idle-states in order to
provide energy-savings as well as shifting power to the active
units. On existing pseries LPARs today we have extended CEDE with
latency-hints {1,2} supported.
In Patches 1-3 of this patchset, we add the code to parse the CEDE
latency records provided by the hypervisor. We use this information to
determine the wakeup latency of the regular CEDE (which we have been
so far hardcoding to 10us while experimentally it is much lesser ~
1us), by looking at the wakeup latency provided by the hypervisor for
Extended CEDE states. Since the platform currently advertises Extended
CEDE 1 to have wakeup latency of 2us, we can be sure that the wakeup
latency of the regular CEDE is no more than this.
Patch 4 (currently marked as RFC), expose the extended CEDE states
parsed above to the cpuidle framework, provided that they can wakeup
on an interrupt. On current platforms only Extended CEDE 1 fits the
bill, but this is going to change in future platforms where even
Extended CEDE 2 may be responsive to external interrupts.
Patch 5 (currently marked as RFC), filters out Extended CEDE 1 since
it offers no added advantage over the normal CEDE.
With Patches 1-3, we see an improvement in the single-threaded
performance on ebizzy.
2 ebizzy threads bound to the same big-core. 25% improvement in the
avg records/s (higher the better) with patches 1-3.
x without_patches
* with_patches
N Min MaxMedian AvgStddev
x 10 2491089 5834307 5398375 4244335 1596244.9
* 10 2893813 5834474 5832448 5327281.3 1055941.4
We do not observe any major regression in either the context_switch2
benchmark or the schbench benchmark
context_switch2 across CPU0 CPU1 (Both belong to same big-core, but different
small cores). We observe a minor 0.14% regression in the number of
context-switches (higher is better).
x without_patch
* with_patch
N Min MaxMedian AvgStddev
x 500348872362236354712 354745.69 2711.827
* 500349422361452353942 354215.4 2576.9258
context_switch2 across CPU0 CPU8 (Different big-cores). We observe a 0.37%
improvement in the number of context-switches (higher is better).
x without_patch
* with_patch
N Min MaxMedian AvgStddev
x 500287956294940288896 288977.23 646.59295
* 500288300294646289582 290064.76 1161.9992
schbench:
No major difference could be seen until the 99.9th percentile.
Without-patch
Latency percentiles (usec)
50.0th: 29
75.0th: 39
90.0th: 49
95.0th: 59
*99.0th: 13104
99.5th: 14672
99.9th: 15824
min=0, max=17993
With-patch:
Latency percentiles (usec)
50.0th: 29
75.0th: 40
90.0th: 50
95.0th: 61
*99.0th: 13648
99.5th: 14768
99.9th: 15664
min=0, max=29812
Gautham R. Shenoy (5):
cpuidle-pseries: Set the latency-hint before entering CEDE
cpuidle-pseries: Add function to parse extended CEDE records
cpuidle-pseries : Fixup exit latency for CEDE(0)
cpuidle-pseries : Include extended CEDE states in cpuidle framework
cpuidle-pseries: Block Extended CEDE(1) which adds no additional
value.
drivers/cpuidle/cpuidle-pseries.c | 268 +-
1 file changed, 266 insertions(+), 2 deletions(-)
--
1.9.4
