[OSSTEST PATCH v2 30/41] sg-report-host-history: Fork

[Ian Jackson <ian.jackson@eu.citrix.com>]

Run each host's report in a separate child.  This is considerably
faster.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
 sg-report-host-history | 47 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/sg-report-host-history b/sg-report-host-history
index f4352fc3..dc694ebe 100755
--- a/sg-report-host-history
+++ b/sg-report-host-history
@@ -34,6 +34,7 @@ our $flightlimit;
 our $htmlout = ".";
 our $read_existing=1;
 our $doinstall=1;
+our $maxjobs=10;
 our @blessings;
 
 open DEBUG, ">/dev/null";
@@ -44,7 +45,7 @@ csreadconfig();
 while (@ARGV && $ARGV[0] =~ m/^-/) {
     $_= shift @ARGV;
     last if m/^--?$/;
-    if (m/^--(limit)\=([1-9]\d*)$/) {
+    if (m/^--(limit|maxjobs)\=([1-9]\d*)$/) {
         $$1= $2;
     } elsif (m/^--time-limit\=([1-9]\d*)$/) {
         $timelimit= $1;
@@ -469,12 +470,44 @@ db_retry($dbh_tests, [], sub {
     computeflightsrange();
 });
 
+undef $dbh_tests;
+
+our %children;
+our $worst = 0;
+
+sub wait_for_max_children ($) {
+    my ($lim) = @_;
+    while (keys(%children) > $lim) {
+	$!=0; $?=0; my $got = wait;
+	die "$! $got $?" unless exists $children{$got};
+	my $host = $children{$got};
+	delete $children{$got};
+	$worst = $? if $? > $worst;
+	if ($?) {
+	    print STDERR "sg-report-flight[: [$got] failed for $host: $?\n";
+	} else {
+	    print DEBUG "REAPED [$got] $host\n";
+	}
+    }
+}
+
 foreach my $host (sort keys %hosts) {
-    read_existing_logs($host);
-    db_retry($dbh_tests, [], sub {
-        mainquery($host);
-	reporthost $host;
-    });
+    wait_for_max_children($maxjobs);
+
+    my $pid = fork // die $!;
+    if (!$pid) {
+	opendb_tests();
+	read_existing_logs($host);
+	db_retry($dbh_tests, [], sub {
+            mainquery($host);
+	    reporthost $host;
+	});
+	print DEBUG "JQ CACHE ".($jqtotal-$jqcachemisses)." / $jqtotal\n";
+	exit(0);
+    }
+    print DEBUG "SPAWNED [$pid] $host\n";
+    $children{$pid} = $host;
 }
 
-print DEBUG "JQ CACHE ".($jqtotal-$jqcachemisses)." / $jqtotal\n";
+wait_for_max_children(0);
+exit $worst;
-- 
2.20.1