[yocto] Parallel builds with common shared state cache

[Brian Karcz]

Hi Ross,

I'm sure the fact that we are still on Edison doesn't increase the odds that any potential lock protection is in place on the cache. Much like your experiences, I haven't seen anything adverse with our previous builds, but the configuration seemed odd and with potential to have problems. I figured since I was in the process of working on the build system and this was right in my face, I'd seek out some input on the configuration's validity.

Thanks,
Brian



-----Original Message-----
From: Burton, Ross [mailto:ross.burton at intel.com] 
Sent: Wednesday, February 05, 2014 9:34 AM
To: Brian Karcz
Cc: yocto at yoctoproject.org
Subject: Re: [yocto] Parallel builds with common shared state cache

On 4 February 2014 18:03, Brian Karcz <briank at russound.com> wrote:
> I’m curious is there are any issues with using a common shared state 
> cache directory, outside the build directory, for multiple different 
> image builds that also might be running in parallel to each other? I’m 
> in the process of setting up a new build server and wanted to make 
> sure this wasn’t an invalid configuration before proceeding.

I'm not positive that there are locks around the sstate cache (although there arguably should be if there isn't), but the worst-case scenario is that one build tries to extract a partial sstate archive, fails because it's truncated, and does the build itself.  It's probably safe enough: my personal AB shares a sstate between its own builders and my own builds without any issues.

Ross