tests: publish: Constrain guix-publish thread use.

On systems with more than 64 processors. Otherwise starting so many threads
during the test will trip resource limits and lead to a spurious failure with
SIGABRT.

I'm seeing this on a 128 core system running Guix, and limiting to just 64
processors seems sufficient.

* tests/publish.scm: Call setaffinity when the current processor count exceeds
64.

Change-Id: Id4c6d7dcc9ae8dd8dafa2587def98f538061425c

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/publish.scm b/tests/publish.scm
index d5ec3c954fa..3c80c50d515 100644
--- a/tests/publish.scm
+++ b/tests/publish.scm
@@ -96,6 +96,20 @@
         (lambda ()
           exp ...)))))
 
+;; guix-publish uses (current-processor-count) as the default number of
+;; workers, however on a system with a large number of cores, that large
+;; number of worker threads being used in the course of these tests can end up
+;; hitting resource limits and causing spurious test failures.
+;;
+;; This will depend on what resource limits are in use, but 64 seems low
+;; enough to be able to run the tests without problems.
+(let ((max-processors 64))
+  (when (> (current-processor-count)
+           max-processors)
+    (setaffinity
+     (getpid)
+     (make-bitvector max-processors #t))))
+
 ;; Run a local publishing server in a separate thread.
 (with-separate-output-ports
  (call-with-new-thread