Re: [bitbake-devel] regression of 'world' performance?

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Fri, 2024-01-12 at 11:57 +0100, Alexander Kanavin wrote:
> there seems to be a noticeable slowdown in bitbake doing world builds,
> particularly when layers in meta-oe are added to it. I've locally
> observed Cooker process spinning at 100% while no or few tasks get
> executed, apparently deciding what to do next, and it is noticeable in
> autobuilder too, e.g. right now:
> https://autobuilder.yoctoproject.org/typhoon/#/builders/88/builds/3515
> 
> I'd like to profile what is happening, but not sure where to start. Suggestions?

I've noticed a few slow builds too but I'm not convinced it is bitbake.

We observed a qemuarm-oecore build take 19 hours and of that,
nativesdk-gcc (for i686) took 6 hours.

It is likely that something else on the machine (maybe in another
build) is probably taking up much of the CPU capacity, e.g. rust
building or something.

The reason I mention the nativesdk-gcc above is that at the point that
is executed, bitbake is pretty much out the equation, it is just
processing logs. Whilst it is possible bitbake is slowing it down, I
find that unlikely and there is probably some other factor at play.

It is worth noting that there is only one build currently running on
alma9-ty-1 where the above build is and there are quite often multiple
tasks completing each second when it updates.

So nothing specific I can suggest but just my observations/thoughts.

You could pull the event log json file from the build and "replay" it
with some new viewer tool to see if there is any specific delay
involved between task executions. The events should be in there to
allow that.

Cheers,

Richard