httpd/async: switch to level-triggered epoll

We'll save ourselves some code here and let the kernel do more
work, instead.

diff --git a/Documentation/technical/ds.txt b/Documentation/technical/ds.txt
index 7bc1ad79ce0c89f1e87e70f4ef50a0afc82a165d..5a1655a1450e2c60018ec487a8c036778ed727e6 100644 (file)
--- a/Documentation/technical/ds.txt
+++ b/Documentation/technical/ds.txt
@@ -77,8 +77,7 @@ New features
   which (if any) events it's interested in for the next loop iteration.
 
 * Edge-triggering available via EPOLLET or EV_CLEAR.  These reduce wakeups
-  for unidirectional classes (e.g. PublicInbox::Listener sockets,
-  and pipes via PublicInbox::HTTPD::Async).
+  for unidirectional classes when throughput is more important than fairness.
 
 * IO::Socket::SSL support (for NNTPS, STARTTLS+NNTP, HTTPS)
 

diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index 7238650aff978605c53213fdd5586f32465f785b..1651da88ac034cfcc022f8739b7ab25246b09975 100644 (file)
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -17,7 +17,7 @@ package PublicInbox::HTTPD::Async;
 use strict;
 use parent qw(PublicInbox::DS);
 use Errno qw(EAGAIN);
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
 
 # This is called via: $env->{'pi-httpd.async'}->()
 # $io is a read-only pipe ($rpipe) for now, but may be a
@@ -39,7 +39,7 @@ sub new {
        }, $class;
        my $pp = tied *$io;
        $pp->{fh}->blocking(0) // die "$io->blocking(0): $!";
-       $self->SUPER::new($io, EPOLLIN | EPOLLET);
+       $self->SUPER::new($io, EPOLLIN);
 }
 
 sub event_step {
@@ -54,15 +54,12 @@ sub event_step {
                my $r = sysread($sock, my $buf, 65536);
                if ($r) {
                        $self->{fh}->write($buf); # may call $http->close
-                       if ($http->{sock}) { # !closed
-                               $self->requeue;
-                               # let other clients get some work done, too
-                               return;
-                       }
+                       # let other clients get some work done, too
+                       return if $http->{sock}; # !closed
 
                        # else: fall through to close below...
                } elsif (!defined $r && $! == EAGAIN) {
-                       return; # EPOLLET means we'll be notified
+                       return; # EPOLLIN means we'll be notified
                }
 
                # Done! Error handling will happen in $self->{fh}->close
@@ -89,9 +86,6 @@ sub async_pass {
 
        $self->{http} = $http;
        $self->{fh} = $fh;
-
-       # either hit EAGAIN or ->requeue to keep EPOLLET happy
-       event_step($self);
 }
 
 # may be called as $forward->close in PublicInbox::HTTP or EOF (event_step)

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index a1ff65b65324e177f9e5adad67dec703183434a7..53d0ad55ee84d47ccc10bd2d7516136fd38207e8 100644 (file)
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -192,7 +192,6 @@ sub event_step {
 sub rd_hdr ($) {
        my ($self) = @_;
        # typically used for reading CGI headers
-       # we must loop until EAGAIN for EPOLLET in HTTPD/Async.pm
        # We also need to check EINTR for generic PSGI servers.
        my $ret;
        my $total_rd = 0;