From 37a7633ded43d657be28586a4f31caad46d38984 Mon Sep 17 00:00:00 2001
From: Robert Lanyi <lanyi.robert.attila@gmail.com>
Date: Sat, 21 Mar 2020 18:44:10 +0100
Subject: [PATCH 1/3] Add THREADS env var to control number of threads

---
 bin/rrd-extractstats.pl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/bin/rrd-extractstats.pl b/bin/rrd-extractstats.pl
index 685f625..31813eb 100755
--- a/bin/rrd-extractstats.pl
+++ b/bin/rrd-extractstats.pl
@@ -44,6 +44,11 @@ my $i :shared = 0;
 
 my $cpus = do { local @ARGV='/proc/cpuinfo'; grep /^processor\s+:/, <>;};
 my $num_workers	= $cpus / 2;
+if (($ENV{'THREADS'} =~ /^\d+$/) and ($ENV{'THREADS'} > 0)) { 
+    $num_workers = $ENV{'THREADS'};
+}
+print("Using " . $num_workers . " threads.\n");
+
 my $num_work_units = scalar @rrdfiles;
 
 my $q = Thread::Queue->new();

From 858c646e01a8d66531b8f036b3a4a5902c8339ef Mon Sep 17 00:00:00 2001
From: Robert Lanyi <lanyi.robert.attila@gmail.com>
Date: Sun, 22 Mar 2020 14:42:07 +0100
Subject: [PATCH 2/3] Change default number of threads to 1 (original behavior)

---
 bin/rrd-extractstats.pl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/bin/rrd-extractstats.pl b/bin/rrd-extractstats.pl
index 31813eb..9a824ab 100755
--- a/bin/rrd-extractstats.pl
+++ b/bin/rrd-extractstats.pl
@@ -42,8 +42,7 @@ my @rrdfiles = File::Find::Rule->maxdepth(2)->file->in($rrdpath);
 $|=1;
 my $i :shared = 0;
 
-my $cpus = do { local @ARGV='/proc/cpuinfo'; grep /^processor\s+:/, <>;};
-my $num_workers	= $cpus / 2;
+my $num_workers	= 1;
 if (($ENV{'THREADS'} =~ /^\d+$/) and ($ENV{'THREADS'} > 0)) { 
     $num_workers = $ENV{'THREADS'};
 }

From a0ffd9d8670844fdd08aa2d976986d13e8ffc2d9 Mon Sep 17 00:00:00 2001
From: Robert Lanyi <lanyi.robert.attila@gmail.com>
Date: Sun, 22 Mar 2020 14:59:37 +0100
Subject: [PATCH 3/3] Fix warning when THREADS env var is missing

---
 bin/rrd-extractstats.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bin/rrd-extractstats.pl b/bin/rrd-extractstats.pl
index 9a824ab..a729720 100755
--- a/bin/rrd-extractstats.pl
+++ b/bin/rrd-extractstats.pl
@@ -43,7 +43,7 @@ $|=1;
 my $i :shared = 0;
 
 my $num_workers	= 1;
-if (($ENV{'THREADS'} =~ /^\d+$/) and ($ENV{'THREADS'} > 0)) { 
+if (($ENV{'THREADS'}) and ($ENV{'THREADS'} =~ /^\d+$/) and ($ENV{'THREADS'} > 0)) { 
     $num_workers = $ENV{'THREADS'};
 }
 print("Using " . $num_workers . " threads.\n");