Re: Bug#770009: convert(1) very slow on mips with no FPU

James Cowgill <[email protected]> Sat, 15 Aug 2015 20:43:42 +0100
Newsgroups	gmane.linux.debian.ports.mips
Message-ID	<[email protected]>
Hi,

On Sat, 2015-08-15 at 14:08 +0100, Simon McVittie wrote:
> (debian-mips: please keep me and the bug in Cc if replying.)
> 
> On Wed, 28 Jan 2015 at 08:00:53 +0100, roucaries bastien wrote:
> > Smell like an openmp bug.... ny memory they are a enviroment variable to
> > disable openmp.
> 
> I tried building with --disable-openmp on a mips porterbox
> (minkus.debian.org, which I believe is a dual Cavium Octeon II with no FPU,
> the same as the buildds where imagemagick has been failing).

Yes, minkus and mips-aql-* all run identical hardware and do not have
FPUs (unfortunately).

> Unfortunately building with --disable-openmp doesn't seem to help.
> 
> On Thu, 29 Jan 2015 at 19:59:45 +0100, Bastien ROUCARIES wrote:
> > try to add to convert command line "-limit thread 1"
> 
> Sadly that doesn't seem to help either.
> 
> > On Fri, Jan 30, 2015 at 2:37 PM, Dejan Latinovic
> > <[email protected]> wrote:
> > > did anyone tried to wait some longer time to see if command will execute?
> > 
> >   No, but the build machines wait for a pretty long time before
> > killing (5 hours), and I've checked that it uses the proc at 200%. We
> > can't burden the build machines like that...
> 
> The latest experimental build (which adds some "echo", to stop sbuild
> killing the build process after 5 hours of apparent inactivity) took
> 19 hours. That's longer than gcc-5 took on the same hardware.
> 
> While doing test builds yesterday evening, I was able to compile
> imagemagick more than once, so it can't have taken longer than 2 or 3 hours;
> assuming the porterbox and the buildd have a similar spec, that means
> converting a SVG to a PNG 14 times is taking at least 16 hours.
> That seems unusably slow to me. It's entirely possible that imagemagick
> built for mips is currently only really useful on mips hardware that has
> a FPU. Unfortunately, the mips buildds don't seem to have FPUs.
> 
> mips porters: how common are FPUs expected to be among mips machines
> where Debian will run?

I have no numbers but I would guess that most of the machines that run
the big endian port are network hardware which don't have FPUs.

> Also, is it an ABI break for a mips library to be built with -msoft-float?
	
Yes the ABI is different - you need a recompiled glibc (at least) to
use -msoft-float.

Thanks,
James
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