From: Eric Wong <e@80x24.org>
To: spew@80x24.org
Subject: [PATCH] multi_accept redux
Date: Wed, 12 Apr 2023 08:26:40 +0000 [thread overview]
Message-ID: <20230412082640.2050679-1-e@80x24.org> (raw)
---
Documentation/public-inbox-daemon.pod | 20 ++++++++++++
lib/PublicInbox/Daemon.pm | 7 ++--
lib/PublicInbox/Listener.pm | 46 +++++++++++++--------------
3 files changed, 48 insertions(+), 25 deletions(-)
diff --git a/Documentation/public-inbox-daemon.pod b/Documentation/public-inbox-daemon.pod
index 81a79a10..6baef717 100644
--- a/Documentation/public-inbox-daemon.pod
+++ b/Documentation/public-inbox-daemon.pod
@@ -115,6 +115,26 @@ per-listener C<cert=> option. The private key may be
concatenated into the path used by the cert, in which case this
option is not needed.
+=item --accept-nr INTEGER
+
+By default, each worker accepts one connection at-a-time to
+maximize fairness across multiple processes on a shared listen
+socket. In deployments with one or few workers, using a
+positive value enables workers to accept the given number of
+client requests on each wakeup at the expense of fairness.
+
+Negative values allows workers to accept all available clients
+on each wakeup. Thus C<-1> is similar to C<multi_accept yes> in
+nginx; while C<1> (the default) is similar to C<multi_accept no>
+in nginx.
+
+Using C<0> is synonmous with C<1>
+
+May be specifed on a per-listener basis via the C<accept-nr=>
+per-listener directive (e.g. C<-l 127.0.0.1?accept-nr=2>).
+
+Default: 1
+
=back
=head1 SIGNALS
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 57435421..f24416e6 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -136,6 +136,7 @@ sub load_mod ($;$$) {
}
my $err = $tlsd->{err};
$tlsd->{warn_cb} = sub { print $err @_ }; # for local $SIG{__WARN__}
+ $xn{'accept-nr'} = $opt->{'accept-nr'}->[-1] if $opt->{'accept-nr'};
\%xn;
}
@@ -167,6 +168,7 @@ EOF
'u|user=s' => \$user,
'g|group=s' => \$group,
'D|daemonize' => \$daemonize,
+ 'accept-nr=i' => \$PublicInbox::Listener::ACCEPT_NR,
'cert=s' => \$default_cert,
'key=s' => \$default_key,
'help|h' => \(my $show_help),
@@ -251,7 +253,7 @@ EOF
$s->blocking(0);
my $sockname = sockname($s);
warn "# bound $scheme://$sockname\n";
- $xnetd->{$sockname} //= load_mod($scheme);
+ $xnetd->{$sockname} //= load_mod($scheme, $opt);
$listener_names->{$sockname} = $s;
push @listeners, $s;
}
@@ -712,7 +714,8 @@ sub daemon_loop ($) {
defer_accept($_, $tls_cb ? 'dataready' : $xn->{af_default});
# this calls epoll_create:
- PublicInbox::Listener->new($_, $tls_cb || $xn->{post_accept})
+ PublicInbox::Listener->new($_, $tls_cb || $xn->{post_accept},
+ $xn->{'accept-nr'})
} @listeners;
PublicInbox::DS::event_loop($sig, $oldset);
}
diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index 7cedc349..d171449f 100644
--- a/lib/PublicInbox/Listener.pm
+++ b/lib/PublicInbox/Listener.pm
@@ -1,14 +1,15 @@
-# Copyright (C) 2015-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
#
# Used by -nntpd for listen sockets
package PublicInbox::Listener;
-use strict;
+use v5.12;
use parent 'PublicInbox::DS';
use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY);
use IO::Handle;
use PublicInbox::Syscall qw(EPOLLIN EPOLLEXCLUSIVE);
use Errno qw(EAGAIN ECONNABORTED);
+our $ACCEPT_NR = 1;
# Warn on transient errors, mostly resource limitations.
# EINTR would indicate the failure to set NonBlocking in systemd or similar
@@ -16,37 +17,36 @@ my %ERR_WARN = map {;
eval("Errno::$_()") => $_
} qw(EMFILE ENFILE ENOBUFS ENOMEM EINTR);
-sub new ($$$) {
- my ($class, $s, $cb) = @_;
+sub new {
+ my ($class, $s, $cb, $accept_nr) = @_;
setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1);
setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
listen($s, 2**31 - 1); # kernel will clamp
my $self = bless { post_accept => $cb }, $class;
+ $self->{accept_nr} = $accept_nr //= $ACCEPT_NR;
+ $self->{accept_nr} = 1 if !$accept_nr;
$self->SUPER::new($s, EPOLLIN|EPOLLEXCLUSIVE);
}
sub event_step {
my ($self) = @_;
my $sock = $self->{sock} or return;
-
- # no loop here, we want to fairly distribute clients
- # between multiple processes sharing the same socket
- # XXX our event loop needs better granularity for
- # a single accept() here to be, umm..., acceptable
- # on high-traffic sites.
- if (my $addr = accept(my $c, $sock)) {
- IO::Handle::blocking($c, 0); # no accept4 :<
- eval { $self->{post_accept}->($c, $addr, $sock) };
- warn "E: $@\n" if $@;
- } elsif ($! == EAGAIN || $! == ECONNABORTED) {
- # EAGAIN is common and likely
- # ECONNABORTED is common with bad connections
- return;
- } elsif (my $sym = $ERR_WARN{int($!)}) {
- warn "W: accept(): $! ($sym)\n";
- } else {
- warn "BUG?: accept(): $!\n";
- }
+ my $n = $self->{accept_nr};
+ do {
+ if (my $addr = accept(my $c, $sock)) {
+ IO::Handle::blocking($c, 0); # no accept4 :<
+ eval { $self->{post_accept}->($c, $addr, $sock) };
+ warn "E: $@\n" if $@;
+ } elsif ($! == EAGAIN || $! == ECONNABORTED) {
+ # EAGAIN is common and likely
+ # ECONNABORTED is common with bad connections
+ return;
+ } elsif (my $sym = $ERR_WARN{int($!)}) {
+ warn "W: accept(): $! ($sym)\n";
+ } else {
+ warn "BUG?: accept(): $!\n";
+ }
+ } while ($n--);
}
1;
reply other threads:[~2023-04-12 8:26 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230412082640.2050679-1-e@80x24.org \
--to=e@80x24.org \
--cc=spew@80x24.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).