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authorEric Wong <e@yhbt.net>2020-02-02 06:52:22 +0000
committerEric Wong <e@yhbt.net>2020-02-02 17:29:59 +0000
commit5bddb0ece15079f9961949d48615b990081e0a95 (patch)
treeebb1e18fb8b476c1f2b30e0284b2ab303dacd4ce
parenta715ce5da88e2263888a92335d794fab0aad91c0 (diff)
downloadpublic-inbox-5bddb0ece15079f9961949d48615b990081e0a95.tar.gz
OpenBSD and FreeBSD support `getconf NPROCESSORS_ONLN` (no
leading underscore).  They may also have GNU nproc installed as
"gnproc".

We may also encounter Linux systems w/o GNU coreutils, but able
to use `getconf _NPROCESSORS_ONLN` (with leading underscore).
-rw-r--r--lib/PublicInbox/V2Writable.pm22
1 files changed, 19 insertions, 3 deletions
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 72d8d5af..82843241 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -7,6 +7,7 @@ package PublicInbox::V2Writable;
 use strict;
 use warnings;
 use base qw(PublicInbox::Lock);
+use 5.010_001;
 use PublicInbox::SearchIdxShard;
 use PublicInbox::MIME;
 use PublicInbox::Git;
@@ -32,14 +33,29 @@ my $PACKING_FACTOR = 0.4;
 # to increase Xapian shards
 our $NPROC_MAX_DEFAULT = 4;
 
+sub detect_nproc () {
+        for my $nproc (qw(nproc gnproc)) { # GNU coreutils nproc
+                `$nproc 2>/dev/null` =~ /^(\d+)$/ and return $1;
+        }
+
+        # getconf(1) is POSIX, but *NPROCESSORS* vars are not
+        for (qw(_NPROCESSORS_ONLN NPROCESSORS_ONLN)) {
+                `getconf $_ 2>/dev/null` =~ /^(\d+)$/ and return $1;
+        }
+
+        # should we bother with `sysctl hw.ncpu`?  Those only give
+        # us total processor count, not online processor count.
+        undef
+}
+
 sub nproc_shards ($) {
         my ($creat_opt) = @_;
         my $n = $creat_opt->{nproc} if ref($creat_opt) eq 'HASH';
         $n //= $ENV{NPROC};
         if (!$n) {
-                chomp($n = `nproc 2>/dev/null`);
-                # assume 2 cores if GNU nproc(1) is not available
-                $n = 2 if !$n;
+                # assume 2 cores if not detectable or zero
+                state $NPROC_DETECTED = detect_nproc() || 2;
+                $n = $NPROC_DETECTED;
                 $n = $NPROC_MAX_DEFAULT if $n > $NPROC_MAX_DEFAULT;
         }