Messages in this thread |  | | Subject | Re: [PATCH v1 1/2] cpufreq: ACPI: Extend frequency tables to cover boost frequencies | From | Giovanni Gherdovich <> | Date | Fri, 05 Feb 2021 08:06:25 +0100 |
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On Thu, 2021-02-04 at 18:25 +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > A severe performance regression on AMD EPYC processors when using > the schedutil scaling governor was discovered by Phoronix.com and > attributed to the following commits: > > 41ea667227ba ("x86, sched: Calculate frequency invariance for > AMD systems") > > 976df7e5730e ("x86, sched: Use midpoint of max_boost and max_P > for frequency invariance on AMD EPYC") > > [snip] > > Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems") > Fixes: 976df7e5730e ("x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC") > Fixes: db865272d9c4 ("cpufreq: Avoid configuring old governors as default with intel_pstate") > Link: https://www.phoronix.com/scan.php?page=article&item=linux511-amd-schedutil&num=1 > Link: https://lore.kernel.org/linux-pm/20210203135321.12253-2-ggherdovich@suse.cz/ > Reported-by: Michael Larabel <Michael@phoronix.com> > Diagnosed-by: Giovanni Gherdovich <ggherdovich@suse.cz> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/cpufreq/acpi-cpufreq.c | 107 ++++++++++++++++++++++++++++++++++++----- > 1 file changed, 95 insertions(+), 12 deletions(-) > > Index: linux-pm/drivers/cpufreq/acpi-cpufreq.c > =================================================================== > --- linux-pm.orig/drivers/cpufreq/acpi-cpufreq.c > +++ linux-pm/drivers/cpufreq/acpi-cpufreq.c > [...]
Tested-by: Giovanni Gherdovich <ggherdovich@suse.cz> Reviewed-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Note there is also the Tested-by: Michael, from the other thread https://lore.kernel.org/lkml/5ea06dbe-255c-3d22-b9bd-6e627c5f94af@phoronix.com/
I tested this patch with the "NASA Parallel Benchmarks" from [link below], the results confirms that the 5.10 performance is recovered:
Ratios of completion times, lower is better (5.10 is the baseline)
5.10 5.11-rc6 5.11-rc6-ggherdov 5.11-rc6-rafael ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Integer Sort 1.00 1.21 0.91 0.93 Embarrassingly Parallel 1.00 1.60 1.00 1.00 Discrete FFT 1.00 1.68 0.67 0.67
CPU : MODEL : 2x AMD EPYC 7742 FREQUENCY TABLE : P2: 1.50 GHz P1: 2.00 GHz P0: 2.25 GHz MAX BOOST : 3.40 GHz
[link] https://www.nas.nasa.gov/publications/npb.html
Thanks, Giovanni
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