tests: disable fsync everywhere

The "GIT_TEST_FSYNC" environment variable now exists for
disabling fsync() even on packfiles and other "critical" data.

Running "make test -j8 NO_SVN_TESTS=1" on a noisy 8-core system
on an HDD, test runtime drops from ~4 minutes down to ~3 minutes.
Using "GIT_TEST_FSYNC=1" re-enables fsync() for comparison
purposes.

SVN interopability tests are minimally affected since SVN will
still use fsync in various places.

This will also be useful for 3rd-party tools which create
throwaway git repositories of temporary data, but remains
undocumented for end users.

Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/git-cvsserver.perl b/git-cvsserver.perl
index 64319be..4c81180 100755
--- a/git-cvsserver.perl
+++ b/git-cvsserver.perl
@@ -3607,6 +3607,22 @@ package GITCVS::updater;
 use strict;
 use warnings;
 use DBI;
+our $_use_fsync;
+
+# n.b. consider using Git.pm
+sub use_fsync {
+    if (!defined($_use_fsync)) {
+        my $x = $ENV{GIT_TEST_FSYNC};
+        if (defined $x) {
+            local $ENV{GIT_CONFIG};
+            delete $ENV{GIT_CONFIG};
+            my $v = ::safe_pipe_capture('git', '-c', "test.fsync=$x",
+                                        qw(config --type=bool test.fsync));
+            $_use_fsync = defined($v) ? ($v eq "true\n") : 1;
+        }
+    }
+    $_use_fsync;
+}
 
 =head1 METHODS
 
@@ -3676,6 +3692,9 @@ sub new
                                 $self->{dbuser},
                                 $self->{dbpass});
     die "Error connecting to database\n" unless defined $self->{dbh};
+    if ($self->{dbdriver} eq 'SQLite' && !use_fsync()) {
+        $self->{dbh}->do('PRAGMA synchronous = OFF');
+    }
 
     $self->{tables} = {};
     foreach my $table ( keys %{$self->{dbh}->table_info(undef,undef,undef,'TABLE')->fetchall_hashref('TABLE_NAME')} )