build-system/gnu: Limit load average.

A nice feature of offload builds is that Guix will throttle the start of
new jobs based on the overload-threshold.  There is no equivalent for
local builds, so one must either run builds in serial (--max-jobs=1) and
endure single-threaded builds or run concurrent builds and watch the
system overload as it runs multiple multi-threaded builds.

From a benchmark comparing the compilation of concurrent Folly builds,
the "max-load" option reduced the overall time by 8.3%. Memory use also
drops considerably since we are only running 1/4 of the processes at any
time.

* guix/build/gnu-build-system.scm (build, check): Set max load.

Change-Id: I97f1e3e59880b6ed23faed2038eb5279415e9c95
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
This commit is contained in:
Greg Hogan 2025-04-01 13:58:17 +00:00 committed by Andreas Enge
parent e239958b8b
commit b2a20e5fd9
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@ -28,6 +28,7 @@
#:use-module (ice-9 regex)
#:use-module (ice-9 format)
#:use-module (ice-9 ftw)
#:use-module (ice-9 threads)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-19)
#:use-module (srfi srfi-34)
@ -386,7 +387,9 @@ makefiles."
#:allow-other-keys)
(apply invoke "make"
`(,@(if parallel-build?
`("-j" ,(number->string (parallel-job-count)))
`("-j" ,(number->string (parallel-job-count))
,(string-append "--max-load="
(number->string (total-processor-count))))
'())
,@make-flags)))
@ -425,7 +428,9 @@ makefiles."
(raise c)))
(apply invoke "make" test-target
`(,@(if parallel-tests?
`("-j" ,(number->string (parallel-job-count)))
`("-j" ,(number->string (parallel-job-count))
,(string-append "--max-load="
(number->string (total-processor-count))))
'())
,@make-flags)))
(format #t "test suite not run~%")))