user/dev discussion of public-inbox itself
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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 04/11] listener: use edge-triggered notifications
Date: Sat, 29 Jun 2019 19:59:44 +0000
Message-ID: <20190629195951.32160-5-e@80x24.org> (raw)
In-Reply-To: <20190629195951.32160-1-e@80x24.org>

We don't need extra wakeups from the kernel when we know a
listener is already active.
---
 lib/PublicInbox/DSKQXS.pm   | 4 +++-
 lib/PublicInbox/Listener.pm | 7 ++++---
 lib/PublicInbox/Syscall.pm  | 4 ++--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/lib/PublicInbox/DSKQXS.pm b/lib/PublicInbox/DSKQXS.pm
index 364df3d6..278d3f88 100644
--- a/lib/PublicInbox/DSKQXS.pm
+++ b/lib/PublicInbox/DSKQXS.pm
@@ -16,7 +16,8 @@ use warnings;
 use parent qw(IO::KQueue);
 use parent qw(Exporter);
 use IO::KQueue;
-use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT EPOLL_CTL_DEL);
+use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT EPOLLET
+	EPOLL_CTL_DEL);
 our @EXPORT_OK = qw(epoll_ctl epoll_wait);
 my $owner_pid = -1; # kqueue is close-on-fork (yes, fork, not exec)
 
@@ -25,6 +26,7 @@ sub kq_flag ($$) {
 	my ($bit, $ev) = @_;
 	if ($ev & $bit) {
 		my $fl = EV_ADD | EV_ENABLE;
+		$fl |= EV_CLEAR if $fl & EPOLLET;
 		($ev & EPOLLONESHOT) ? ($fl | EV_ONESHOT) : $fl;
 	} else {
 		EV_ADD | EV_DISABLE;
diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index 94b2aed4..594dabb8 100644
--- a/lib/PublicInbox/Listener.pm
+++ b/lib/PublicInbox/Listener.pm
@@ -9,6 +9,7 @@ use base 'PublicInbox::DS';
 use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
 use fields qw(post_accept);
 require IO::Handle;
+use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE EPOLLET);
 
 sub new ($$$) {
 	my ($class, $s, $cb) = @_;
@@ -17,15 +18,14 @@ sub new ($$$) {
 	listen($s, 1024);
 	IO::Handle::blocking($s, 0);
 	my $self = fields::new($class);
-	$self->SUPER::new($s, PublicInbox::DS::EPOLLIN()|
-	                      PublicInbox::DS::EPOLLEXCLUSIVE());
+	$self->SUPER::new($s, EPOLLIN|EPOLLET|EPOLLEXCLUSIVE);
 	$self->{post_accept} = $cb;
 	$self
 }
 
 sub event_step {
 	my ($self) = @_;
-	my $sock = $self->{sock};
+	my $sock = $self->{sock} or return;
 
 	# no loop here, we want to fairly distribute clients
 	# between multiple processes sharing the same socket
@@ -35,6 +35,7 @@ sub event_step {
 	if (my $addr = accept(my $c, $sock)) {
 		IO::Handle::blocking($c, 0); # no accept4 :<
 		$self->{post_accept}->($c, $addr, $sock);
+		$self->requeue;
 	}
 }
 
diff --git a/lib/PublicInbox/Syscall.pm b/lib/PublicInbox/Syscall.pm
index 500efa67..d7e15c72 100644
--- a/lib/PublicInbox/Syscall.pm
+++ b/lib/PublicInbox/Syscall.pm
@@ -22,7 +22,7 @@ use vars qw(@ISA @EXPORT_OK %EXPORT_TAGS $VERSION);
 $VERSION     = "0.25";
 @ISA         = qw(Exporter);
 @EXPORT_OK   = qw(sendfile epoll_ctl epoll_create epoll_wait
-                  EPOLLIN EPOLLOUT
+                  EPOLLIN EPOLLOUT EPOLLET
                   EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
                   EPOLLONESHOT EPOLLEXCLUSIVE);
 %EXPORT_TAGS = (epoll => [qw(epoll_ctl epoll_create epoll_wait
@@ -39,7 +39,7 @@ use constant EPOLLOUT      => 4;
 # use constant EPOLLRDBAND   => 128;
 use constant EPOLLEXCLUSIVE => (1 << 28);
 use constant EPOLLONESHOT => (1 << 30);
-# use constant EPOLLET => (1 << 31);
+use constant EPOLLET => (1 << 31);
 use constant EPOLL_CTL_ADD => 1;
 use constant EPOLL_CTL_DEL => 2;
 use constant EPOLL_CTL_MOD => 3;
-- 
EW


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-29 19:59 [PATCH 00/11] ds: more updates Eric Wong
2019-06-29 19:59 ` [PATCH 01/11] ds: share lazy rbuf handling between HTTP and NNTP Eric Wong
2019-06-29 19:59 ` [PATCH 02/11] ds: move requeue logic over from NNTP Eric Wong
2019-06-29 19:59 ` [PATCH 03/11] http: use requeue instead of watch_in1 Eric Wong
2019-06-29 19:59 ` Eric Wong [this message]
2019-06-29 19:59 ` [PATCH 05/11] ds: handle deferred DS->close after timers Eric Wong
2019-06-29 19:59 ` [PATCH 06/11] ds: consolidate IO::Socket::SSL checks Eric Wong
2019-06-29 19:59 ` [PATCH 07/11] http: support HTTPS (kinda) Eric Wong
2019-06-29 19:59 ` [PATCH 08/11] parentpipe: document and use one-shot wakeups Eric Wong
2019-06-29 19:59 ` [PATCH 09/11] parentpipe: make the ->close call more obvious Eric Wong
2019-06-29 19:59 ` [PATCH 10/11] httpd/async: switch to buffering-as-fast-as-possible Eric Wong
2019-06-29 19:59 ` [PATCH 11/11] http: use bigger, but shorter-lived buffers for pipes Eric Wong

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