Raspberry Pi 3B+ high Load Average

[sadko4u]

Yesterday installed latest Arch Linux build on Raspberry Pi 3B+ with 32 GB SD card.

Today I've noticed that on an idle system, I get Load Average 4 reported by htop:
https://imgur.com/a/0yaV9fn

System is also idle in iostat:
$this->bbcode_second_pass_quote('', '
')Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn
mmcblk0 0.00 0.00 0.00 0 0

[sadko4u]

Also I see the following in dmesg:
$this->bbcode_second_pass_code('', '
[ 18.767064] ------------[ cut here ]------------
[ 18.772098] irq 79 handler irq_default_primary_handler+0x0/0x20 enabled interrupts
[ 18.780217] WARNING: CPU: 0 PID: 0 at kernel/irq/handle.c:153 __handle_irq_event_percpu+0x22c/0x248
[ 18.789738] Modules linked in: btsdio brcmfmac rc_cec vc4 brcmutil cec microchip rc_core drm_kms_helper drm hci_uart drm_panel_orientation_quirks joydev cfg80211 btqca btbcm btintel syscopyarea sysfillrect lan78xx bcm2835_v4l2(C) sysimgblt bluetooth fb_sys_fops v4l2_common videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videobuf2_common videodev ecdh_generic rfkill i2c_bcm2835 bcm2835_thermal pwm_bcm2835 snd_bcm2835(C) media bcm2835_wdt
[ 18.832311] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G C 5.0.1-1-ARCH #1
[ 18.840558] Hardware name: Raspberry Pi 3 Model B+ (DT)
[ 18.846057] pstate: 20000005 (nzCv daif -PAN -UAO)
[ 18.851107] pc : __handle_irq_event_percpu+0x22c/0x248
[ 18.856516] lr : __handle_irq_event_percpu+0x22c/0x248
[ 18.861919] sp : ffff000010003c80
[ 18.865405] x29: ffff000010003c80 x28: ffff0000117bc000
[ 18.870994] x27: 0000000000000002 x26: ffff8000332cec00
[ 18.876582] x25: ffff0000115a0018 x24: ffff0000115bd708
[ 18.882169] x23: ffff000010003d34 x22: 0000000000000000
[ 18.887754] x21: 000000000000004f x20: ffff8000332cec00
[ 18.893342] x19: ffff800035328900 x18: 0000000000000010
[ 18.898932] x17: 0000000000000000 x16: 0000000000000000
[ 18.904519] x15: 0000000000aaaaaa x14: ffff0000115bd6c8
[ 18.910104] x13: 0000000000000001 x12: 00000000ffffffff
[ 18.915690] x11: ffff000008ed2098 x10: 0000000000000001
[ 18.921278] x9 : 0000000000000001 x8 : ffff000010815e90
[ 18.926866] x7 : 0000000000000000 x6 : 0000000000000001
[ 18.932452] x5 : 0000000000000000 x4 : 0000000000000001
[ 18.938039] x3 : 0000000000000000 x2 : 0000000000000004
[ 18.943624] x1 : fb81bac429241300 x0 : 0000000000000000
[ 18.949212] Call trace:
[ 18.951805] __handle_irq_event_percpu+0x22c/0x248
[ 18.956855] handle_irq_event_percpu+0x40/0x98
[ 18.961536] handle_irq_event+0x50/0xa8
[ 18.965576] handle_simple_irq+0xa8/0xe8
[ 18.969706] generic_handle_irq+0x34/0x50
[ 18.973944] intr_complete+0x8c/0x178 [lan78xx]
[ 18.978713] __usb_hcd_giveback_urb+0x74/0x130
[ 18.983387] usb_giveback_urb_bh+0xf4/0x188
[ 18.987794] tasklet_action_common.isra.2+0xa4/0x168
[ 18.993018] tasklet_hi_action+0x2c/0x38
[ 18.997146] __do_softirq+0x130/0x330
[ 19.001002] irq_exit+0xc0/0xd0
[ 19.004309] __handle_domain_irq+0x70/0xc0
[ 19.008619] bcm2836_arm_irqchip_handle_irq+0x74/0xd8
[ 19.013930] el1_irq+0xb0/0x140
[ 19.017238] arch_cpu_idle+0x34/0x1b8
[ 19.021096] do_idle+0x218/0x290
[ 19.024494] cpu_startup_entry+0x28/0x30
[ 19.028626] rest_init+0xb8/0xc4
[ 19.032029] arch_call_rest_init+0x14/0x1c
[ 19.036341] start_kernel+0x428/0x450
[ 19.040196] ---[ end trace 99462335eeda868f ]---
')

[lategoodbye]

Even this looks very scary, it ain't so:

https://github.com/raspberrypi/linux/issues/2881

Unfortunately there is no fix for both issues upstream

[sadko4u]

Thanks for a link.

[lategoodbye]

The fixes are now in staging-next and will be scheduled for Linux 5.3:
https://patchwork.kernel.org/cover/10937233/

[2sdude]

Thanks for indicating that the fix will be in 5.3. How do I get 5.3 for my aarch64/rpi 3 b+? Will pacman give it or do I need to (cross-)compile it myself? I now have 5.1.10-1.

I ask because my RPi 2 is still at version 4.19 (which I am fine with but I wanted to use the touch screen with kernel support on RPi 3).

[lategoodbye]

There is no 5.3, even 5.2 hasn't released yet:
http://phb-crystal-ball.org/

So i looks like you need to build the kernel on your own or hope that the patches are backported for Arch Linux.

[arch404]

Why can't the aarch64 kernel be patched now? I've been waiting for over 100 days to upgrade to the 5.x kernel and now I have to wait until September at earliest? I don't get it why they couldn't have included it in say 5.1 ? This is wait is painful.

[moonman]

$this->bbcode_second_pass_quote('arch404', 'W')hy can't the aarch64 kernel be patched now? I've been waiting for over 100 days to upgrade to the 5.x kernel and now I have to wait until September at earliest? I don't get it why they couldn't have included it in say 5.1 ? This is wait is painful.

[navik]

The issue is not at all a cosmetic one; the device is running hotter at idle than being reported by users not observing a high CPU idle load, indicating that some kind of computation is taking place, perhaps on the GPU.

$this->bbcode_second_pass_code('', 'sensors') report stable temperature at >60C, whilst reports are that <50C is to be expected for the device. See https://raspberrypi.stackexchange.com/questions/56611/is-this-idle-temperature-normal-for-the-rpi-3