Messages in this thread | | | Date | Wed, 10 Feb 2021 10:23:39 +0100 | From | Pali Rohár <> | Subject | Re: [PATCH mvebu v2 00/10] Armada 37xx: Fix cpufreq changing base CPU speed to 800 MHz from 1000 MHz |
| |
On Tuesday 09 February 2021 18:07:41 nnet wrote: > On Tue, Feb 9, 2021, at 5:51 PM, nnet wrote: > > On Tue, Feb 9, 2021, at 5:31 PM, nnet wrote: > > > On Tue, Feb 9, 2021, at 3:26 PM, Marek Behún wrote: > > > > On Tue, 09 Feb 2021 15:16:45 -0800 > > > > nnet <nnet@fastmail.fm> wrote: > > > > > > > > > I've two of these and I've just swapped them (and re-pasted the heat sinks). > > > > > > > > > > The second one ran under load for awhile and now has frozen as well. > > > > > > > > > > Under a moderate load `wget -O /dev/null <large.bin>` @X00Mbits they are fine. > > > > > > > > > > Under a 1 min speed test of load ~200Mbits routed WireGuard they freeze. > > > > > > > > > > They fine with both those workloads @1000_800. > > > > > > > > > > Perhaps it's heat? Unfortunately I don't have any numbers on that ATM. > > > > > > > > Try disabling cpufreq in kernel completely, compile boot image at > > > > 1200 MHz. If it continues freezing, then I fear we can't help you with > > > > 1200 MHz :( > > > > > > cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies > > > 200000 300000 600000 1200000 > > > > > > I'm not getting any freezes with 1.2GHz fixed after 20 minutes of load: > > > > > > echo 1200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq > > > > > > Setting it back to min 200MHz I get a freeze within a minute: > > > > > > echo 200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq
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
(of course on 1.2 GHz variant you need to adjust values as only following frequencies 200000 300000 600000 1200000 are supported)
> > > > Marek > > > > > > > > > +#define MIN_VOLT_MV_FOR_L0_L1_1GHZ 1108 > > > > Based on the below at boot time might an equivalent of the above need > > to be 1225 for 1.2GHz? > > > > 1200_750 > > SVC REV: 5, CPU VDD voltage: 1.225V > > > > 1000_800 > > SVC REV: 5, CPU VDD voltage: 1.108V
This value is printed in WTMI avs.c by following code:
shift = OTP_SVC_SPEED_1000_OFF; (OR) shift = OTP_SVC_SPEED_1200_OFF;
vdd_otp = ((otp_data[OTP_DATA_SVC_SPEED_ID] >> shift) + AVS_VDD_BASE) & AVS_VDD_MASK; regval |= (vdd_otp << HIGH_VDD_LIMIT_OFF); regval |= (vdd_otp << LOW_VDD_LIMIT_OFF); printf("SVC REV: %d, CPU VDD voltage: %s\n", svc_rev, avis_dump[vdd_otp].desc);
So voltage value is read from the OTP memory.
But I do not know what this value means.
> I did this for a quick test for 1.2GHz: > > +#define MIN_VOLT_MV_FOR_L0_L1_1GHZ 1225 > > This is working well so far. Frequency is shifting up/down with load applied/stopped.
| |