git: async: flatten the inflight array

Small array refs have considerable overhead in Perl, so reduce
AV/SV overhead and instead allow the inflight array to grow
twice as large.

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 8426cc7d6a705488e8dded3bd0691fd412e0a372..e1d5c386e7ebdeffde31f33637deeac28eb7d7ea 100644 (file)
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -18,7 +18,7 @@ use base qw(Exporter);
 our @EXPORT_OK = qw(git_unquote git_quote);
 
 use constant MAX_INFLIGHT =>
-       ($^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF())
+       (($^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF()) * 2)
        /
        65; # SHA-256 hex size + "\n" in preparation for git using non-SHA1
 
@@ -135,8 +135,8 @@ sub read_cat_in_full ($$) {
 
 sub _cat_async_step ($$) {
        my ($self, $inflight) = @_;
-       my $pair = shift @$inflight or die 'BUG: inflight empty';
-       my ($cb, $arg) = @$pair;
+       die 'BUG: inflight empty or odd' if scalar(@$inflight) < 2;
+       my ($cb, $arg) = splice(@$inflight, 0, 2);
        local $/ = "\n";
        my $head = readline($self->{in});
        $head =~ / missing$/ and return
@@ -314,7 +314,7 @@ sub cat_async ($$$;$) {
        }
 
        print { $self->{out} } $oid, "\n" or fail($self, "write error: $!");
-       push(@$inflight, [ $cb, $arg ]);
+       push(@$inflight, $cb, $arg);
 }
 
 sub extract_cmt_time {