# an estimate of the post-packed size to the raw uncompressed size
my $PACKING_FACTOR = 0.4;
-# assume 2 cores if GNU nproc(1) is not available
+# SATA storage lags behind what CPUs are capable of, so relying on
+# nproc(1) can be misleading and having extra Xapian partions is a
+# waste of FDs and space. It can also lead to excessive IO latency
+# and slow things down. Users on NVME or other fast storage can
+# use the NPROC env or switches in our script/public-inbox-* programs
+# to increase Xapian partitions.
+our $NPROC_MAX_DEFAULT = 4;
+
sub nproc_parts ($) {
my ($creat_opt) = @_;
if (ref($creat_opt) eq 'HASH') {
}
}
- my $n = int($ENV{NPROC} || `nproc 2>/dev/null` || 2);
+ my $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;
+ $n = $NPROC_MAX_DEFAULT if $NPROC_MAX_DEFAULT > 4;
+ }
+
# subtract for the main process and git-fast-import
$n -= 1;
$n < 1 ? 1 : $n;