[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Danny Milosavljevic]

* gnu/packages/rust.scm (rust-1.26)[arguments]<#:phases>[check]: Enable
parallel tests.
---
 gnu/packages/rust.scm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gnu/packages/rust.scm b/gnu/packages/rust.scm
index 63426a12fc..23b28cce23 100644
--- a/gnu/packages/rust.scm
+++ b/gnu/packages/rust.scm
@@ -724,6 +724,11 @@ jemalloc = \"" jemalloc "/lib/libjemalloc_pic.a" "\"
           `(modify-phases ,phases
              ;; binaryen was replaced with LLD project from LLVM
              (delete 'dont-build-native)
+             (replace 'check
+               (lambda* _
+                 ;; Enable parallel execution.
+                 (invoke "./x.py" (string-append "-j" (number->string (parallel-job-count))) "test" "-vv")
+                 (invoke "./x.py" (string-append "-j" (number->string (parallel-job-count))) "test" "src/tools/cargo")))
              (replace 'remove-unsupported-tests
                (lambda* _
                  ;; Our ld-wrapper cannot process non-UTF8 bytes in LIBRARY_PATH.

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Ivan Petkov]

Functionally, it looks good to me (and should speed up all subsequent builds)!

Just curious, any reason why we’re doing this starting 1.26 and not earlier?

—Ivan

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Danny Milosavljevic]

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Hi Ivan,

On Wed, 3 Apr 2019 17:52:35 -0700
Ivan Petkov <ivanppetkov@gmail.com> wrote:

> Functionally, it looks good to me (and should speed up all subsequent builds)!
> 
> Just curious, any reason why we’re doing this starting 1.26 and not earlier?

There have been problems with it in very old Rust builds which is why it was
disabled in the first place.

Icecat uses Rust 1.24 - I selfishly don't want to change that one because I
use it ;)

And I'm not sure when (in which version) they fixed the parallel tests (if
they fixed them, that is).

So I'm kinda starting in the middle...

(I'm now up to and excluding rust 1.30.1 with enabled parallel tests with -j4)
(rust 1.30.1 is still building for a few rounds)

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[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Ivan Petkov]

Hi Danny,

> On Apr 4, 2019, at 11:29 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:
> 
> There have been problems with it in very old Rust builds which is why it was
> disabled in the first place.
> 
> Icecat uses Rust 1.24 - I selfishly don't want to change that one because I
> use it ;)

Can’t say that I fault you there, I really hate having to rebootstrap the entire rust chain ;)

> And I'm not sure when (in which version) they fixed the parallel tests (if
> they fixed them, that is).
> 
> So I'm kinda starting in the middle...

We can always try moving it up to earlier versions as necessary, so I’m fine with landing
this as long as all the later tests build fine!

—Ivan

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Danny Milosavljevic]

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All tests of all Rust >= 1.26 just successfully completed--with parallel tests.

Should we limit the number of parallel jobs?  I think at least armhf is going
to be very overloaded otherwise.  To which value?

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[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Ivan Petkov]

Hi Danny,

> On Apr 5, 2019, at 7:11 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:
> 
> Should we limit the number of parallel jobs?  I think at least armhf is going
> to be very overloaded otherwise.  To which value?

Do the armhf builders define that they have fewer cores available?

If not, we could cap the max jobs to 2, although it would be nice to potentially
use as many cores as are available for non-armhf builds.

—Ivan

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Danny Milosavljevic]

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On Fri, 5 Apr 2019 08:36:44 -0700
Ivan Petkov <ivanppetkov@gmail.com> wrote:

> Hi Danny,
> 
> > On Apr 5, 2019, at 7:11 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:
> > 
> > Should we limit the number of parallel jobs?  I think at least armhf is going
> > to be very overloaded otherwise.  To which value?  
> 
> Do the armhf builders define that they have fewer cores available?
> 
> If not, we could cap the max jobs to 2, although it would be nice to potentially
> use as many cores as are available for non-armhf builds.

I think the problem is RAM usage.  Arm machines have little RAM and will choke
if too many memory-expensive things run in parallel.

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[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Ivan Petkov]

> On Apr 6, 2019, at 3:48 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:
> 
> On Fri, 5 Apr 2019 08:36:44 -0700
> Ivan Petkov <ivanppetkov@gmail.com> wrote:
> 
>> Hi Danny,
>> 
>>> On Apr 5, 2019, at 7:11 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:
>>> 
>>> Should we limit the number of parallel jobs?  I think at least armhf is going
>>> to be very overloaded otherwise.  To which value?  
>> 
>> Do the armhf builders define that they have fewer cores available?
>> 
>> If not, we could cap the max jobs to 2, although it would be nice to potentially
>> use as many cores as are available for non-armhf builds.
> 
> I think the problem is RAM usage.  Arm machines have little RAM and will choke
> if too many memory-expensive things run in parallel.

I’d anticipate that building rustc itself would be the most memory intense operation,
I think most of the individual tests aren’t anywhere nearly as big…

—Ivan

[bug#35126] [PATCH] gnu: rust: Enable parallel tests starting with 1.26.

[Ivan Petkov]

Hi Danny,

When it’s time to merge this in, would you mind also changing the
`generate-checksums` procedure in (guix build cargo-utils) to omit
the `src-name` parameter (as mentioned in #35155)?

If we’re going to be having the CI bootstrap almost the whole rustc
chain for this change, we might as well combine them together and
build all at once!

Thanks,
—Ivan