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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 2/4] evcleanup: micro-optimize asap function
Date: Sat, 25 Jun 2016 00:45:31 +0000
Message-Id: <20160625004533.5061-3-e@80x24.org>
In-Reply-To: <20160625004533.5061-1-e@80x24.org>
References: <20160625004533.5061-1-e@80x24.org>
List-Id: <meta@public-inbox.org>

Instead of relying on a timer with immediate callback,
arm a pipe to watch for writability, ensuring the callback
always fires.
---
 lib/PublicInbox/EvCleanup.pm | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/lib/PublicInbox/EvCleanup.pm b/lib/PublicInbox/EvCleanup.pm
index 5efb093..61837b8 100644
--- a/lib/PublicInbox/EvCleanup.pm
+++ b/lib/PublicInbox/EvCleanup.pm
@@ -5,32 +5,56 @@
 package PublicInbox::EvCleanup;
 use strict;
 use warnings;
+use base qw(Danga::Socket);
+use fields qw(rd);
+my $singleton;
+my $asapq = [ [], undef ];
+my $laterq = [ [], undef ];
 
-my $asapq = { queue => [], timer => undef };
-my $laterq = { queue => [], timer => undef };
+sub once_init () {
+	my $self = fields::new('PublicInbox::EvCleanup');
+	my ($r, $w);
+	pipe($r, $w) or die "pipe: $!";
+	$self->SUPER::new($w);
+	$self->{rd} = $r; # never read, since we never write..
+	$self;
+}
 
 sub _run_all ($) {
 	my ($q) = @_;
 
-	my $run = $q->{queue};
-	$q->{queue} = [];
-	$q->{timer} = undef;
+	my $run = $q->[0];
+	$q->[0] = [];
+	$q->[1] = undef;
 	$_->() foreach @$run;
 }
 
 sub _run_asap () { _run_all($asapq) }
 sub _run_later () { _run_all($laterq) }
 
+# Called by Danga::Socket
+sub event_write {
+	my ($self) = @_;
+	$self->watch_write(0);
+	_run_asap();
+}
+
+sub _asap_timer () {
+	$singleton ||= once_init();
+	$singleton->watch_write(1);
+	1;
+}
+
 sub asap ($) {
 	my ($cb) = @_;
-	push @{$asapq->{queue}}, $cb;
-	$asapq->{timer} ||= Danga::Socket->AddTimer(0, *_run_asap);
+	push @{$asapq->[0]}, $cb;
+	$asapq->[1] ||= _asap_timer();
 }
 
 sub later ($) {
 	my ($cb) = @_;
-	push @{$laterq->{queue}}, $cb;
-	$laterq->{timer} ||= Danga::Socket->AddTimer(60, *_run_later);
+	push @{$laterq->[0]}, $cb;
+	$laterq->[1] ||= Danga::Socket->AddTimer(60, *_run_later);
 }
 
 END {