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Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline
From: |
Jan Hudec |
Subject: |
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline] |
Date: |
Wed, 23 Jun 2004 09:38:28 +0200 |
User-agent: |
Mutt/1.5.6+20040523i |
On Tue, Jun 22, 2004 at 22:21:34 -0700, Tom Lord wrote:
>
> > From: Colin Walters <address@hidden>
> > On Tue, 2004-06-22 at 19:15 -0700, Tom Lord wrote:
>
> > > GCC commits happen too fast (last I checked) to serialize them while
> > > inserting tests between each one.
>
> > > I.e., just naively dropping a "make test" call into your PQM just
> > > before the "tla commit" --- probably the commit queue will grow
> > > without bound (until the developers notice and say, hey, this isn't
> > > working :-).
>
> > How else would you do it? You could run the tests in parallel, which
> > would scale up faster with more CPUs, but if you want to enforce the
> > invariant that the test suite passes for every commit on the mainline -
> > you have to run the test suite for every commit.
>
>
> So, to sum up...... if you want a process that says:
>
>
> while (pending patch)
> if (test is ok)
> commit
>
> then your patch queue is rate limited by the greater of the commit
> time and the test time. Test time for GCC will strongly dominate.
>
> Speeding up test times, through any combination of parallel builds,
> cached build results, precompiled headers etc --- are therefore,
> indeed, useful ways to raise the maximum commit rate of the above
> loop.
>
> But there's an upper bound on that commit rate and, for now anyway,
> I'm just pretending we know that the maximum commit rate for that loop
> is too low.
>
> That's not a bad thing to pretend. _Absent_ compilation and
> test-execution speed-ups, the test rate is already too high to keep up
> with GCC commits. [To be clear: that's my rough recollection, not a
> proven result that I'm claiming. It's my envelope calculation, not a
> proven fact.]
>
> Are the compilation and test-execution speed-ups viable? In the long
> run as testing procedures get more complex? I doubt it. Remember
> that, ideally, these tests are repeated on several platforms.
> Nevermind that they can be done in parallel -- just pushing around the
> bits is already going to get you in trouble.
1) The current gcc approach, as I understood it, is, that before commit,
each developer runs a test. If it then breaks because someone else
commited a conflicting patch, it is resolved ex-post. So without the
tests, arch-pqm would perform exactly as cvs does now.
2) A star of patch-queues. Since pqm can do star-merge, it would be
possible to have several testing pqm-based branches. Merge requests
first go there, are tested, and if they work, get merged into the
mainline and tested as a bunch. The individual testing queues should
be probably grouped by subsytems or features to be most useful.
-------------------------------------------------------------------------------
Jan 'Bulb' Hudec
<address@hidden>
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- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], (continued)
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Charles Duffy, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/22
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Colin Walters, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Colin Walters, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Robert Collins, 2004/06/26
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/22
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Colin Walters, 2004/06/22
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline],
Jan Hudec <=
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Andrew Suffield, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tom Lord, 2004/06/23
- Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], James Blackwell, 2004/06/23
[Gnu-arch-users] round 2 of GCC v. Arch, Tom Lord, 2004/06/23
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Colin Walters, 2004/06/23
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tobias C. Rittweiler, 2004/06/23
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Colin Walters, 2004/06/23
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Tobias C. Rittweiler, 2004/06/23
Re: [Gnu-arch-users] GCC v. Arch address@hidden: Regressions on mainline], Aaron Bentley, 2004/06/23