On Thu, Jul 30, 2020 at 01:06:46PM -0400, Robbie Harwood wrote:
"Richard W.M. Jones" <rjones(a)redhat.com> writes:
> On Thu, Jul 30, 2020 at 11:46:08AM -0400, Robbie Harwood wrote:
>> Aleksandra Fedorova <alpha(a)bookwar.info> writes:
>>
>>> As COPR has recently got support for s390 builds, the question is:
>>> if emulation is good enough for building packages, can we use it for
>>> testing? What are the limitations there? Is it worth it?
>>
>> Cross-architecture emulation is unbelievably slow in the general
>> case. While it helps for some specific use cases, it's not a
>> substitute for actually getting hardware.
>
> Since qemu TCG now supports host thread per vCPU you can usually throw
> lots of vCPUs at the problem, assuming your builds can be parallelised
> and your x86 hardware has plenty of cores.
That's good to know, and definitely I could see that helping with builds
themselves, but won't help with many (most?) test suites :)
This is sadly true for many :-(
For nbdkit though, our test suite will use as many ‘make -j #cores’ as
you can throw at it (I have tested 64) :-)
Rich.
--
Richard Jones, Virtualization Group, Red Hat
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