1102200 - Composing time becomes much longer randomly when we unplug the usb cable on flame-kk device

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: the compositor time when we unplug usb cable.

When we turn on vsync on flame-kk, with OMTA animation, we got a very uniform composing time for each frame. Bug if we unplug the usb cable, we can see a lot of janks during animation.

If we force to use the performance cpu governor, we will not see this issue.
  adb shell "echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

I think it might related to cpu power module.

Android provide some performance hint for user[1].
I set both POWER_HINT_VSYNC and POWER_HINT_INTERACTION hint into our power module in GonkDisplay[2], but it seems not work.

[1]
http://androidxref.com/4.4.4_r1/xref/hardware/libhardware/include/hardware/power.h
[2]
http://dxr.mozilla.org/mozilla-central/source/widget/gonk/libdisplay/GonkDisplayJB.cpp?from=GonkDisplayJB.cpp&case=true#158

Comment 1

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: adbwifi.sh

I use this script to turn on wifi adb for device.

1) turn on the wifi on device and connect to your ap
2) ./adbwifi.sh
   if success, you will see "connected to x.x.x.x:5555"
3) unplug the usb cable

After that, I can do profile without usb cable.

Comment 2

[Jerry Shih[:jerry] (UTC+8) (inactive)]

We don't have the power module source code for flame device, so I use nexus5-l instead.
In b2g/hardware/qcom/power/power.c, it will write some data to "/dev/socket/pb" with POWER_HINT_INTERACTION hint. And the unix domain socket "/dev/socket/pb" seems created by mpdecision. I can't trace the mpdecision either. Still tracking.

  case POWER_HINT_INTERACTION:
    touch_boost();
    break;
  case POWER_HINT_VSYNC:
    //do nothing
    break;

Comment 3

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Is it a good idea having a module in gonk to set the cpu governor in gecko? Since we might not always have a power module to handle the android "POWER_HINT_INTERACTION" and "POWER_HINT_VSYNC" hint. Maybe we should write our power hint module.
When we have touch data or enable the vsync, we change the governor as [1].

[1]
echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Comment 4

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: cpu governor hint. v1

Comment 5

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: cpu governor hint. v2

Comment 6

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: profile result for omta animatoin with power hint

Here is the profile result for omta animation with power hint.
With performance mode, we still can't recover the long compositor composing time.

Comment 7

[Michael Wu [:mwu]]

At the moment, configuration of the cpu governor is the responsibility of the vendor. This usually makes the most sense since CPU speed needs to also take thermal conditions into account. More complicated things like ARM big.LITTLE usually have their own cpu governor (AIUI), so we can't even assume a particular governor.

Comment 8

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: create a new gonk power module

Create a new power module to handle all power related function. It also moves all power related code from GonkDisplay to this GonkPower module.

Comment 9

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: Set vsync power hint when we enable vsync. v1

Comment 10

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Comment on attachment 8568969 [details] [diff] [review]
create a new gonk power module

It's hard to configure the cpu governor by ourself, but we still have the android's power hint. No matter our vender implements the hint or not, I think we still can set the hint to the power module.

This patch create a new power module to export the following power hint[1] from android. I also move all power module related code from GonkDisplay to this module to make GonkDisplay much clearer. Then, we set the hint as the attachment 8568970 [details] [diff] [review].

[1]
http://androidxref.com/4.4.4_r1/xref/hardware/libhardware/include/hardware/power.h#41

Comment 11

[Michael Wu [:mwu]]

Not sure what the purpose of that patch is. It doesn't seem any easier to understand if you move it to another file.

Comment 12

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: set vsync power hint when we enable vsync. v2

Comment 13

[Jerry Shih[:jerry] (UTC+8) (inactive)]

Attachment: add power hint interface in gonkdisplay. v1

Comment 14

[Farmer Tseng[:fatseng](inactive)]

Hi Alexandre,
What do you want to discuss?

Comment 15

[:gerard-majax]

(In reply to Farmer Tseng from comment #14)
> Hi Alexandre,
> What do you want to discuss?

Well this is aligned with the email thread about PowerHAL and luckily I found this bug. Maybe we should work on fixing that? And verify if maybe there is a problem on Flame KK and not on other devices since we now have other devices ?

Comment 16

[:gerard-majax]

Attachment: Bug XXX - Leverage PowerHAL r=...

Comment 17

[:gerard-majax]

This might be useful/interesting for you

Comment 18

[Julien Wajsberg [:julienw]]

Does not seem to change anything for me, but I haven't tried during a long time.

Comment 19

[:gerard-majax]

Attachment: Bug XXX - Leverage PowerHAL r=...

Comment 20

[Gabriele Svelto [:gsvelto]]

I've finally got time to try this out. One good test case is the lockscreen: with the Flame unplugged scrolling the lock icon on the bottom is very janky (like ***VERY*** janky, it looks like it's doing 3-4FPS). With the cable plugged it's super-smooth so if this fixes that particular scenario I think it fixes all of them.

Comment 21

[Gabriele Svelto [:gsvelto]]

Scratch my previous comment, after further testing with Julien it seems that's does't always happen and may be unrelated :-/

Comment 22

[Gabriele Svelto [:gsvelto]]

I'm trying to profile the compositor thread but for some reason it doesn't work, I use this command:

./profile.sh -p b2g -i 1 -t GeckoMain,Compositor

but when I capture the profile I only get data from the GeckoMain thread... I'm I doing something wrong?

Comment 23

[Gabriele Svelto [:gsvelto]]

Clearing the ni for now since this is not super-important right now but I'll definitely come back and have a look once we're done with the transitioning effort.

Comment 24

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee didn't login in Bugzilla in the last 7 months, so the assignee is being reset.