From: nnet <nnet@fastmail.fm>
To: "Pali Rohár" <pali@kernel.org>
Cc: "Marek Behún" <kabel@kernel.org>,
andrew@lunn.ch, luka.perkov@sartura.hr, sboyd@kernel.org,
gregory.clement@bootlin.com, a.heider@gmail.com,
linux-kernel@vger.kernel.org, vladimir.vid@sartura.hr,
mturquette@baylibre.com, rmk+kernel@armlinux.org.uk,
tmn505@gmail.com, gerald@gk2.net, miquel.raynal@bootlin.com,
kostap@marvell.com, linux-clk@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH mvebu v2 00/10] Armada 37xx: Fix cpufreq changing base CPU speed to 800 MHz from 1000 MHz
Date: Thu, 11 Feb 2021 12:22:52 -0800 [thread overview]
Message-ID: <1ad78446-4a40-4c3e-8680-6dbf19616515@www.fastmail.com> (raw)
In-Reply-To: <20210211195559.n2j4jnchl2ho54mg@pali>
On Thu, Feb 11, 2021, at 11:55 AM, Pali Rohár wrote:
> On Wednesday 10 February 2021 11:08:59 nnet wrote:
> > On Wed, Feb 10, 2021, at 10:03 AM, Pali Rohár wrote:
> > > > > Hello! Could you please enable userspace governor during kernel
> > > > > compilation?
> > > > >
> > > > > CONFIG_CPU_FREQ_GOV_USERSPACE=y
> > > > >
> > > > > It can be activated via command:
> > > > >
> > > > > echo userspace > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > >
> > > > > After that you can "force" CPU frequency to specific value, e.g.:
> > > > >
> > > > > echo 1000000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed
> > > > >
> > > > > I need to know which switch (from --> to freq) cause this system hang.
> > > > >
> > > > > This patch series (via MIN_VOLT_MV_FOR_L0_L1_1GHZ) is fixing only
> > > > > switching from 500 MHz to 1000 MHz on 1 GHz variant. As only this switch
> > > > > is causing issue.
> > > > >
> > > > > I have used following simple bash script to check that switching between
> > > > > 500 MHz and 1 GHz is stable:
> > > > >
> > > > > while true; do
> > > > > echo 1000000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > echo 500000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > echo 1000000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > echo 500000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > done
> > > >
> > > > echo userspace | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > while true; do
> > > > echo 1200000 | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > echo 600000 | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > done
> > > >
> > > > >> +#define MIN_VOLT_MV_FOR_L0_L1_1GHZ 1108
> > > >
> > > > With 1108 I get a freeze within a minute. The last output to stdout is 600000.
> > > >
> > > > With 1120 it takes a few minutes.
> > > >
> > > > With any of 1225, 1155, 1132 the device doesn't freeze over the full 5 minute load test.
> > > >
> > > > I'm using ondemand now with the above at 1132 without issue so far.
> > >
> > > Great, thank you for testing!
> > >
> > > Can you check if switching between any two lower frequencies 200000
> > > 300000 600000 is stable?
> >
> > This is stable using 1132 mV for MIN_VOLT_MV_FOR_L0_L1_1GHZ:
> >
> > while true; do
> > # down
> > echo 1200000 | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> ...
>
> Hello!
>
> Could you please re-run test without tee, in form as I have shown above?
> UART is slow and printing something to console adds delay which decrease
> probability that real issue is triggered as this is timing issue.
The test was done over SSH.
> Also please do tests just between two frequencies in loop as I observed
> that switching between more decreased probability to hit issue.
> > > > echo userspace | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > while true; do
> > > > echo 1200000 | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > echo 600000 | tee /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > done
The first test ^ switched between 600 MHz and 1.2 GHz.
> The real issue for 1 GHz variant of A3720 is only when doing switch from
> 500 MHz to 1 GHz. So could you try to do some tests also without
> changing MIN_VOLT_MV_FOR_L0_L1_1GHZ and switching just between non-1.2
> frequencies (to verify that on 1.2 GHz variant it is also from 600 MHz
> to 1.2 GHz)?
With 1108 mV and switching between 600 MHz and 1.2GHz, I always saw a freeze within a minute.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-02-11 20:24 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <d59ba191-43db-4b7b-b201-62a60ca752c0@www.fastmail.com>
2021-02-09 21:33 ` [PATCH mvebu v2 00/10] Armada 37xx: Fix cpufreq changing base CPU speed to 800 MHz from 1000 MHz Pali Rohár
2021-02-09 21:45 ` nnet
2021-02-09 22:42 ` Pali Rohár
2021-02-09 22:52 ` nnet
2021-02-09 22:56 ` Pali Rohár
2021-02-09 23:16 ` nnet
2021-02-09 23:26 ` Marek Behún
2021-02-10 1:31 ` nnet
2021-02-10 1:51 ` nnet
2021-02-10 2:07 ` nnet
2021-02-10 9:23 ` Pali Rohár
2021-02-10 17:34 ` nnet
2021-02-10 18:03 ` Pali Rohár
2021-02-10 19:08 ` nnet
2021-02-10 19:18 ` Marek Behún
2021-02-11 19:55 ` Pali Rohár
2021-02-11 20:22 ` nnet [this message]
2021-02-11 23:44 ` Pali Rohár
2021-02-12 0:41 ` nnet
2021-02-13 10:01 ` Pali Rohár
2021-02-13 18:30 ` nnet
2021-02-14 12:33 ` Pali Rohár
2021-02-16 5:48 ` nnet
2021-02-16 10:41 ` Pali Rohár
2021-02-16 16:27 ` nnet
2021-02-19 19:33 ` Pali Rohár
2021-02-22 3:17 ` nnet
2021-02-22 9:51 ` Pali Rohár
2021-02-22 16:36 ` nnet
2021-02-22 16:40 ` Philip Soares
2021-02-10 2:12 ` Marek Behún
2021-01-14 12:40 Pali Rohár
2021-02-01 14:35 ` Tomasz Maciej Nowak
2021-02-03 19:29 ` Anders Trier Olesen
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=1ad78446-4a40-4c3e-8680-6dbf19616515@www.fastmail.com \
--to=nnet@fastmail.fm \
--cc=a.heider@gmail.com \
--cc=andrew@lunn.ch \
--cc=gerald@gk2.net \
--cc=gregory.clement@bootlin.com \
--cc=kabel@kernel.org \
--cc=kostap@marvell.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luka.perkov@sartura.hr \
--cc=miquel.raynal@bootlin.com \
--cc=mturquette@baylibre.com \
--cc=pali@kernel.org \
--cc=rmk+kernel@armlinux.org.uk \
--cc=sboyd@kernel.org \
--cc=tmn505@gmail.com \
--cc=vladimir.vid@sartura.hr \
/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).