doc: various comments on async handling

Notes for future developers (myself included) since we
can't assume people can read my mind.

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm
index 5f351a77..a3a2015b 100644
--- a/lib/PublicInbox/Listener.pm
+++ b/lib/PublicInbox/Listener.pm
@@ -13,7 +13,7 @@ require IO::Handle;
 sub new ($$$) {
         my ($class, $s, $cb) = @_;
         setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1);
-        setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1);
+        setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); # ignore errors on non-TCP
         listen($s, 1024);
         IO::Handle::blocking($s, 0);
         my $self = fields::new($class);
@@ -26,8 +26,12 @@ sub new ($$$) {
 sub event_read {
         my ($self) = @_;
         my $sock = $self->{sock};
+
         # 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 :<
                 $self->{post_accept}->($c, $addr, $sock);