ipc: switch to one-way pipes

This fixes a performance regression in multi-process v2 indexing
due to the switch to PublicInbox::IPC.  While Unix sockets are
fewer FDs to manage, pipes allow unprivileged processes to use
larger buffers (up to 1M) on out-of-the-box Linux instances.

A larger buffer via F_SETPIPE_SZ afforded by pipes was proven
valuable during v2 development in 2018 and continues to be
valuable when we get significant amounts of one-way traffic from
the producer parent to worker children.

Compression may be an option for systems without F_SETPIPE_SZ;
but it increases CPU usage with no memory bandwidth savings on
hosts where larger buffers are available.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index c4efbdd2..6be95979 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -823,7 +823,7 @@ sub content_exists ($$$) {
 sub atfork_child {
         my ($self) = @_;
         if (my $older_siblings = $self->{idx_shards}) {
-                $_->shard_atfork_child for @$older_siblings;
+                $_->ipc_sibling_atfork_child for @$older_siblings;
         }
         if (my $im = $self->{im}) {
                 $im->atfork_child;