From: "Doug Smythies" <dsmythies@telus.net>
To: "'Giovanni Gherdovich'" <ggherdovich@suse.cz>,
"'Srinivas Pandruvada'" <srinivas.pandruvada@linux.intel.com>,
"'Thomas Gleixner'" <tglx@linutronix.de>,
"'Ingo Molnar'" <mingo@redhat.com>,
"'Peter Zijlstra'" <peterz@infradead.org>,
"'Borislav Petkov'" <bp@suse.de>, "'Len Brown'" <lenb@kernel.org>,
"'Rafael J . Wysocki'" <rjw@rjwysocki.net>
Cc: <x86@kernel.org>, <linux-pm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
"'Mel Gorman'" <mgorman@techsingularity.net>,
"'Matt Fleming'" <matt@codeblueprint.co.uk>,
"'Viresh Kumar'" <viresh.kumar@linaro.org>,
"'Juri Lelli'" <juri.lelli@redhat.com>,
"'Paul Turner'" <pjt@google.com>,
"'Vincent Guittot'" <vincent.guittot@linaro.org>,
"'Quentin Perret'" <qperret@qperret.net>,
"'Dietmar Eggemann'" <dietmar.eggemann@arm.com>
Subject: RE: [PATCH v4 1/6] x86,sched: Add support for frequency invariance
Date: Mon, 25 Nov 2019 00:16:15 -0800 [thread overview]
Message-ID: <000001d5a368$9eece830$dcc6b890$@net> (raw)
In-Reply-To: <000001d5a29b$c944fd70$5bcef850$@net>
On 2019.11.23 23:50 Doug Smythies wrote:
> Hi all,
>
> The address list here is likely incorrect,
> and this e-mail is really about a kernel 5.4
> bisected regression.
>
> It had been since mid September, and kernel 5.3-rc8 since
> I had tried this, so I wanted to try it again. Call it due diligence.
> I focused on my own version of the "gitsource" test.
>
> Kernel 5.4-rc8 (as a baseline reference).
>
> My results were extremely surprising.
>
> As it turns out, at least on my test computer, both the
> acpi-cpufreq and intel_cpufreq CPU frequency scaling drivers
> using the schedutil governor are broken. For the tests that
> I ran, there is negligible difference between them and the
> performance governor. So, one might argue that they are not
> broken, but rather working incredibly well, which if true
> then this patch is no longer needed.
Should be able to gain better insight here with the
intel_pstate_tracer.py utility, watching for differences
in rates of rotation between CPUs. Too late tonight.
>
> I bisected the kernel and got:
>
> first bad commit: [04cbfba6208592999d7bfe6609ec01dc3fde73f5]
> Merge tag 'dmaengine-5.4-rc1' of git://git.infradead.org/users/vkoul/slave-dma
>
> Which did not make any sense at all. I don't even know how
> this is being pulled into my kernel compile.
> O.K., I often (usually) make a mistake
> during bisection, so I did it again, and got the same result.
>
> Relevant excerpt from the commit:
>
> diff --cc drivers/dma/Kconfig
> index 413efef,03fa0c5..7c511e3
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@@ -294,8 -294,8 +294,8 @@@ config INTEL_IOATDM
> If unsure, say N.
>
> config INTEL_IOP_ADMA
> - tristate "Intel IOP ADMA support"
> - depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
> + tristate "Intel IOP32x ADMA support"
> - depends on ARCH_IOP32X
> ++ depends on ARCH_IOP32X || COMPILE_TEST
> select DMA_ENGINE
> select ASYNC_TX_ENABLE_CHANNEL_SWITCH
> help
>
> If I revert the above, manually, then everything behaves
> as expected (minimally tested only, so far).
>
> Are others seeing the schedutil governors not working as
> expected with any of kernels 5.4-rc1 - 5.4-rc8?
>
> I do have a pretty graph of my method of doing the
> "gitsource" test, but am not ready to post it yet.
Graphs and write up (mostly the same as herein) are now
here:
http://www.smythies.com/~doug/linux/single-threaded/k54regression/index.html
The graphs are rather crowded, sorry.
> Here is some gitsource test data, 6 runs of "make test",
> the first run is discarded:
>
> "gg 6" means this 6 patch set.
>
> Kernel 5.4-rc8 + revert, intel_cpufreq/schedutil: 3899 seconds
> Kernel 5.4-rc8 + gg 6 + revert, intel_cpufreq/schedutil: 2740.7 seconds
> Ratio: 0.70 (as expected)
Kernel 5.4-rc8 + gg 6 + revert, forced CPU affinity performance: 2106.5 seconds
> Kernel 5.4-rc8, intel_cpufreq/schedutil: 2334.7 seconds (faster than expected)
> Kernel 5.4-rc8 + gg 6 patch set, intel_cpufreq/schedutil: 2275.0 seconds (faster than expected)
> Ratio: 0.97 (not as expected)
> Kernel 5.4-rc8, intel_cpufreq/performance: 2215.3 seconds
> Kernel 5.4-rc8, intel_cpufreq/ondemand: 3286.3 seconds
> Re-stated from previous e-mail:
> Kernel 5.3-rc8, intel_cpufreq/schedutil: ratio: 0.69 (I don't have the original times)
... Doug
next prev parent reply other threads:[~2019-11-25 8:16 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-13 12:46 [PATCH v4 0/6] Add support for frequency invariance for (some) x86 Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 1/6] x86,sched: Add support for frequency invariance Giovanni Gherdovich
2019-11-24 7:49 ` Doug Smythies
2019-11-25 8:16 ` Doug Smythies [this message]
2019-11-25 9:16 ` Mel Gorman
2019-11-25 16:06 ` Giovanni Gherdovich
2019-11-26 5:59 ` Doug Smythies
2019-11-26 15:20 ` Giovanni Gherdovich
2019-11-27 7:32 ` Doug Smythies
2019-11-28 22:48 ` Doug Smythies
2019-12-19 10:48 ` Qais Yousef
2019-12-23 7:47 ` Doug Smythies
2019-12-23 14:07 ` Qais Yousef
2019-12-23 14:40 ` Qais Yousef
2019-12-23 16:34 ` Doug Smythies
2019-12-23 19:10 ` Qais Yousef
2019-12-24 1:16 ` Doug Smythies
2019-12-24 11:08 ` Qais Yousef
2019-12-02 16:34 ` Ionela Voinescu
2019-12-06 11:57 ` Giovanni Gherdovich
2019-12-18 19:34 ` Peter Zijlstra
2019-12-19 20:27 ` Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 2/6] x86,sched: Add support for frequency invariance on SKYLAKE_X Giovanni Gherdovich
2019-12-18 20:06 ` Peter Zijlstra
2019-12-19 20:29 ` Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 3/6] x86,sched: Add support for frequency invariance on XEON_PHI_KNL/KNM Giovanni Gherdovich
2019-12-18 20:22 ` Peter Zijlstra
2019-12-19 20:32 ` Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 4/6] x86,sched: Add support for frequency invariance on ATOM_GOLDMONT* Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 5/6] x86,sched: Add support for frequency invariance on ATOM Giovanni Gherdovich
2019-11-13 16:50 ` Srinivas Pandruvada
2019-11-15 10:34 ` Giovanni Gherdovich
2019-11-13 12:46 ` [PATCH v4 6/6] x86: intel_pstate: handle runtime turbo disablement/enablement in freq. invariance Giovanni Gherdovich
2019-12-18 20:37 ` [PATCH v4 0/6] Add support for frequency invariance for (some) x86 Peter Zijlstra
2019-12-19 20:33 ` Giovanni Gherdovich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='000001d5a368$9eece830$dcc6b890$@net' \
--to=dsmythies@telus.net \
--cc=bp@suse.de \
--cc=dietmar.eggemann@arm.com \
--cc=ggherdovich@suse.cz \
--cc=juri.lelli@redhat.com \
--cc=lenb@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=matt@codeblueprint.co.uk \
--cc=mgorman@techsingularity.net \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=qperret@qperret.net \
--cc=rjw@rjwysocki.net \
--cc=srinivas.pandruvada@linux.intel.com \
--cc=tglx@linutronix.de \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).