* [PATCH 09/11] watch: use EOFpipe to reduce dwaitpid wakeups
2020-08-31 4:41 7% [PATCH 00/11] watch: fix contention w/ Maildir & NNTP Eric Wong
@ 2020-08-31 4:41 6% ` Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2020-08-31 4:41 UTC (permalink / raw)
To: meta
It's a bit inefficient to use a pipe, here. However, using
dwaitpid() on a process that's not expected to exit soon is
also inefficient as it causes excessive wakeups as most of
our inbox-writing code expects synchronous waitpid().
This only affects -watch instances configured for NNTP and IMAP
clients.
---
MANIFEST | 1 +
lib/PublicInbox/EOFpipe.pm | 24 ++++++++++++++++++++++++
lib/PublicInbox/Watch.pm | 25 +++++++++++++++++++++----
3 files changed, 46 insertions(+), 4 deletions(-)
create mode 100644 lib/PublicInbox/EOFpipe.pm
diff --git a/MANIFEST b/MANIFEST
index f090175e..0b3835d8 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -114,6 +114,7 @@ lib/PublicInbox/DSPoll.pm
lib/PublicInbox/Daemon.pm
lib/PublicInbox/DirIdle.pm
lib/PublicInbox/DummyInbox.pm
+lib/PublicInbox/EOFpipe.pm
lib/PublicInbox/Emergency.pm
lib/PublicInbox/Eml.pm
lib/PublicInbox/EmlContentFoo.pm
diff --git a/lib/PublicInbox/EOFpipe.pm b/lib/PublicInbox/EOFpipe.pm
new file mode 100644
index 00000000..489caf82
--- /dev/null
+++ b/lib/PublicInbox/EOFpipe.pm
@@ -0,0 +1,24 @@
+# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+package PublicInbox::EOFpipe;
+use strict;
+use parent qw(PublicInbox::DS);
+use PublicInbox::Syscall qw(EPOLLIN EPOLLONESHOT);
+
+sub new {
+ my (undef, $rd, $cb, $arg) = @_;
+ my $self = bless { cb => $cb, arg => $arg }, __PACKAGE__;
+ # 1031: F_SETPIPE_SZ, 4096: page size
+ fcntl($rd, 1031, 4096) if $^O eq 'linux';
+ $self->SUPER::new($rd, EPOLLIN|EPOLLONESHOT);
+}
+
+sub event_step {
+ my ($self) = @_;
+ if ($self->do_read(my $buf, 1) == 0) { # auto-closed
+ $self->{cb}->($self->{arg});
+ }
+}
+
+1;
diff --git a/lib/PublicInbox/Watch.pm b/lib/PublicInbox/Watch.pm
index db8d0396..17786377 100644
--- a/lib/PublicInbox/Watch.pm
+++ b/lib/PublicInbox/Watch.pm
@@ -14,7 +14,8 @@ use PublicInbox::Sigfd;
use PublicInbox::DS qw(now);
use PublicInbox::MID qw(mids);
use PublicInbox::ContentHash qw(content_hash);
-use POSIX qw(_exit);
+use PublicInbox::EOFpipe;
+use POSIX qw(_exit WNOHANG);
sub compile_watchheaders ($) {
my ($ibx) = @_;
@@ -611,17 +612,30 @@ sub imap_idle_reap { # PublicInbox::DS::dwaitpid callback
\&imap_idle_requeue, [ $self, $url_intvl ]);
}
+sub reap { # callback for EOFpipe
+ my ($pid, $cb, $self) = @{$_[0]};
+ my $ret = waitpid($pid, 0);
+ if ($ret == $pid) {
+ $cb->($self, $pid); # poll_fetch_reap || imap_idle_reap
+ } else {
+ warn "W: waitpid($pid) => ", $ret // "($!)", "\n";
+ }
+}
+
sub imap_idle_fork ($$) {
my ($self, $url_intvl) = @_;
my ($url, $intvl) = @$url_intvl;
+ pipe(my ($r, $w)) or die "pipe: $!";
defined(my $pid = fork) or die "fork: $!";
if ($pid == 0) {
+ close $r;
watch_atfork_child($self);
watch_imap_idle_1($self, $url, $intvl);
+ close $w;
_exit(0);
}
$self->{idle_pids}->{$pid} = $url_intvl;
- PublicInbox::DS::dwaitpid($pid, \&imap_idle_reap, $self);
+ PublicInbox::EOFpipe->new($r, \&reap, [$pid, \&imap_idle_reap, $self]);
}
sub event_step {
@@ -689,24 +703,27 @@ sub watch_nntp_fetch_all ($$) {
sub poll_fetch_fork ($) { # DS::add_timer callback
my ($self, $intvl, $urls) = @{$_[0]};
return if $self->{quit};
+ pipe(my ($r, $w)) or die "pipe: $!";
my $oldset = watch_atfork_parent($self);
my $pid = fork;
if (defined($pid) && $pid == 0) {
+ close $r;
watch_atfork_child($self);
if ($urls->[0] =~ m!\Aimaps?://!i) {
watch_imap_fetch_all($self, $urls);
} else {
watch_nntp_fetch_all($self, $urls);
}
+ close $w;
_exit(0);
}
PublicInbox::Sigfd::sig_setmask($oldset);
die "fork: $!" unless defined $pid;
$self->{poll_pids}->{$pid} = [ $intvl, $urls ];
- PublicInbox::DS::dwaitpid($pid, \&poll_fetch_reap, $self);
+ PublicInbox::EOFpipe->new($r, \&reap, [$pid, \&poll_fetch_reap, $self]);
}
-sub poll_fetch_reap { # PublicInbox::DS::dwaitpid callback
+sub poll_fetch_reap {
my ($self, $pid) = @_;
my $intvl_urls = delete $self->{poll_pids}->{$pid} or
die "BUG: PID=$pid (unknown) reaped: \$?=$?\n";
^ permalink raw reply related [relevance 6%]
* [PATCH 00/11] watch: fix contention w/ Maildir & NNTP
@ 2020-08-31 4:41 7% Eric Wong
2020-08-31 4:41 6% ` [PATCH 09/11] watch: use EOFpipe to reduce dwaitpid wakeups Eric Wong
0 siblings, 1 reply; 2+ results
From: Eric Wong @ 2020-08-31 4:41 UTC (permalink / raw)
To: meta
Here's a bunch of fixes to improve watch performance when
both Maildirs and NNTP are being watched (possibly on the same
inbox, or if `watchspam' is configured for spam removals).
Wakeups are reduced, and inbox.lock contention is minimized by
using read-only ->over to check for `watchspam' removals.
These affect IMAP, too; but I've been mainly using NNTP.
Eric Wong (11):
watch: limit batch size of NNTP and IMAP workers, too
watchmaildir: use v5.10.1, drop warnings
rename WatchMaildir => Watch
watch: log signal activities to STDERR
watch: avoid unnecessary spawning on spam removals
watch: block signals before fork on non-signalfd/kevent systems
watch: comments and tiny cleanups
ds: avoid excessive queueing when reaping PIDs
watch: use EOFpipe to reduce dwaitpid wakeups
ds: avoid unnecessary timer for waitpid
replace ParentPipe with EOFpipe
MANIFEST | 4 +-
lib/PublicInbox/DS.pm | 38 +++---
lib/PublicInbox/Daemon.pm | 6 +-
lib/PublicInbox/EOFpipe.pm | 24 ++++
lib/PublicInbox/Import.pm | 3 +
lib/PublicInbox/ParentPipe.pm | 23 ----
lib/PublicInbox/V2Writable.pm | 3 +
lib/PublicInbox/{WatchMaildir.pm => Watch.pm} | 111 +++++++++++++-----
script/public-inbox-watch | 34 ++++--
t/imapd.t | 2 +-
t/nntpd.t | 2 +-
t/watch_filter_rubylang.t | 4 +-
t/watch_imap.t | 4 +-
t/watch_maildir.t | 18 +--
t/watch_maildir_v2.t | 22 ++--
t/watch_multiple_headers.t | 4 +-
t/watch_nntp.t | 4 +-
17 files changed, 190 insertions(+), 116 deletions(-)
create mode 100644 lib/PublicInbox/EOFpipe.pm
delete mode 100644 lib/PublicInbox/ParentPipe.pm
rename lib/PublicInbox/{WatchMaildir.pm => Watch.pm} (92%)
^ permalink raw reply [relevance 7%]
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2020-08-31 4:41 7% [PATCH 00/11] watch: fix contention w/ Maildir & NNTP Eric Wong
2020-08-31 4:41 6% ` [PATCH 09/11] watch: use EOFpipe to reduce dwaitpid wakeups Eric Wong
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