Mailinglist Archive: opensuse-buildservice (67 mails)

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Re: [opensuse-buildservice] Increasing the throughput of Open Build Service (OBS) building packages in obs with fusion io pci-e drive card

On Monday 2012-12-10 06:41, Claudio Freire wrote:
On Sun, Dec 9, 2012 at 4:40 PM, Jan Engelhardt <jengelh@xxxxxxx> wrote:
Reason for asking.
Improve the packaging times during busy times on (OBS).

The problem is not disk, it's CPU.

For example, build11 is a 2-core Opteron 8214 according to CPUID,
but is configured for 24 parallel gcc instances [WORKER_INSTANCES=6,
WORKER_JOBS=4]. It is only natural to feel "slow" with these
"overbooking" settings.

Or don't overbook?

What's the rationale for that WORKER_JOBS=4 there?

Basically, to have all CPUs utilized at all times in the event that
other worker instances are idle or I/O-bound. It is quite a sensible
decision. Certainly, WORKER_JOBS=<number of CPUs in the physical
machine> would be sufficient for that, i.e. WORKER_JOBS=2 for build11.

And then, you do not want WORKER_JOBS=1, so that you have a chance to
catch packages who stupidly broke parallel building.

Solving the over-booking problem is made harder by the use of virtual
machines. So far, one way I have found to position the fist near the
eye is by

1. using WORKER_INSTANCES=<number of CPUs> [or desired utilization]
2. Making obs-worker use
instead of the default
%_smp_mflags -jWORKER_JOBS

I tell you, make -l is awesome magic; it sort of autobalances your
obs process tree between "1 worker using 24 gccs" and "24 workers using
1 gcc each" roughly. Needless to say, this requires that one always
looks at the *host's* load, so make -l out of the box is useless for
VM builds ATM.
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