From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=ALL_TRUSTED,BAYES_00 shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 902911FA19 for ; Sun, 3 Jan 2021 02:06:18 +0000 (UTC) From: Eric Wong To: meta@public-inbox.org Subject: [PATCH 6/7] ipc: switch to one-way pipes Date: Sun, 3 Jan 2021 02:06:16 +0000 Message-Id: <20210103020617.15719-7-e@80x24.org> In-Reply-To: <20210103020617.15719-1-e@80x24.org> References: <20210103020617.15719-1-e@80x24.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: 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. --- lib/PublicInbox/IPC.pm | 115 +++++++++++++++++------------- lib/PublicInbox/SearchIdxShard.pm | 23 +++--- lib/PublicInbox/V2Writable.pm | 2 +- 3 files changed, 78 insertions(+), 62 deletions(-) diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm index 6b7b3c7a..c1f6f920 100644 --- a/lib/PublicInbox/IPC.pm +++ b/lib/PublicInbox/IPC.pm @@ -6,7 +6,6 @@ package PublicInbox::IPC; use strict; use v5.10.1; -use Socket qw(AF_UNIX SOCK_STREAM); use Carp qw(confess croak); use PublicInbox::Sigfd; my ($enc, $dec); @@ -34,39 +33,42 @@ if ($enc && $dec) { # should be custom ops } sub _get_rec ($) { - my ($sock) = @_; - local $/ = "\n"; - defined(my $len = <$sock>) or return; + my ($r) = @_; + defined(my $len = <$r>) or return; chop($len) eq "\n" or croak "no LF byte in $len"; - defined(my $r = read($sock, my $buf, $len)) or croak "read error: $!"; - $r == $len or croak "short read: $r != $len"; + defined(my $n = read($r, my $buf, $len)) or croak "read error: $!"; + $n == $len or croak "short read: $n != $len"; thaw($buf); } sub _send_rec ($$) { - my ($sock, $ref) = @_; + my ($w, $ref) = @_; my $buf = freeze($ref); - print $sock length($buf), "\n", $buf or croak "print: $!"; + print $w length($buf), "\n", $buf or croak "print: $!"; } sub ipc_return ($$$) { - my ($s2, $ret, $exc) = @_; - _send_rec($s2, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret); + my ($w, $ret, $exc) = @_; + _send_rec($w, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret); } -sub ipc_worker_loop ($$) { - my ($self, $s2) = @_; - while (my $rec = _get_rec($s2)) { - my ($wantarray, $sub, @args) = @$rec; - if (!defined($wantarray)) { # no waiting if client doesn't care +sub ipc_worker_loop ($$$) { + my ($self, $r_req, $w_res) = @_; + my ($rec, $wantarray, $sub, @args); + local $/ = "\n"; + while ($rec = _get_rec($r_req)) { + ($wantarray, $sub, @args) = @$rec; + # no waiting if client doesn't care, + # this is the overwhelmingly likely case + if (!defined($wantarray)) { eval { $self->$sub(@args) }; - eval { warn "die: $@ (from nowait $sub)\n" } if $@; + eval { warn "$$ die: $@ (from nowait $sub)\n" } if $@; } elsif ($wantarray) { my @ret = eval { $self->$sub(@args) }; - ipc_return($s2, \@ret, $@); - } else { + ipc_return($w_res, \@ret, $@); + } else { # '' => wantscalar my $ret = eval { $self->$sub(@args) }; - ipc_return($s2, \$ret, $@); + ipc_return($w_res, \$ret, $@); } } } @@ -75,33 +77,34 @@ sub ipc_worker_loop ($$) { sub ipc_worker_spawn { my ($self, $ident, $oldset) = @_; return unless $enc; # no Sereal or Storable - my $pid = $self->{-ipc_worker_pid}; - confess "BUG: already spawned PID:$pid" if $pid; - confess "BUG: already have worker socket" if $self->{-ipc_sock}; - my ($s1, $s2); - socketpair($s1, $s2, AF_UNIX, SOCK_STREAM, 0) or die "socketpair: $!"; + return if ($self->{-ipc_ppid} // -1) == $$; # idempotent + delete(@$self{qw(-ipc_req -ipc_res -ipc_ppid -ipc_pid)}); + pipe(my ($r_req, $w_req)) or die "pipe: $!"; + pipe(my ($r_res, $w_res)) or die "pipe: $!"; my $sigset = $oldset // PublicInbox::Sigfd::block_signals(); my $parent = $$; $self->ipc_atfork_parent; - defined($pid = fork) or die "fork: $!"; + defined(my $pid = fork) or die "fork: $!"; if ($pid == 0) { eval { PublicInbox::DS->Reset }; $self->{-ipc_parent_pid} = $parent; - close $s1 or die "close(\$s1): $!"; - $s2->autoflush(1); + $w_req = $r_res = undef; + $w_res->autoflush(1); $SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT)); local $0 = $ident; PublicInbox::Sigfd::sig_setmask($oldset); my $on_destroy = $self->ipc_atfork_child; - eval { ipc_worker_loop($self, $s2) }; + eval { ipc_worker_loop($self, $r_req, $w_res) }; die "worker $ident PID:$$ died: $@\n" if $@; exit; } PublicInbox::Sigfd::sig_setmask($sigset) unless $oldset; - close $s2 or die "close(\$s2): $!"; - $s1->autoflush(1); - $self->{-ipc_sock} = $s1; - $self->{-ipc_worker_pid} = $pid; + $r_req = $w_res = undef; + $w_req->autoflush(1); + $self->{-ipc_req} = $w_req; + $self->{-ipc_res} = $r_res; + $self->{-ipc_ppid} = $$; + $self->{-ipc_pid} = $pid; } sub ipc_worker_reap { # dwaitpid callback @@ -122,15 +125,18 @@ sub ipc_worker_exit { # idempotent, can be called regardless of whether worker is active or not sub ipc_worker_stop { my ($self) = @_; - my $pid; - my $s1 = delete $self->{-ipc_sock} or do { - $pid = delete $self->{-ipc_worker_pid} and - die "unexpected PID:$pid without ipc_sock"; - return; - }; - $pid = delete $self->{-ipc_worker_pid} or die "no PID?"; - _send_rec($s1, [ undef, 'ipc_worker_exit', 0 ]); - shutdown($s1, 2) or die "shutdown(\$s1) for PID:$pid"; + my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)}); + my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)}); + if (!$w_req && !$r_res) { + die "unexpected PID:$pid without IPC pipes" if $pid; + return; # idempotent + } + die 'no PID with IPC pipes' unless $pid; + _send_rec($w_req, [ undef, 'ipc_worker_exit', 0 ]); + $w_req = $r_res = undef; + + # allow any sibling to send ipc_worker_exit, but siblings can't wait + return if $$ != $ppid; eval { my $reap = $self->can('ipc_worker_reap'); PublicInbox::DS::dwaitpid($pid, $reap, $self); @@ -153,17 +159,30 @@ sub ipc_lock_init { # call $self->$sub(@args), on a worker if ipc_worker_spawn was used sub ipc_do { my ($self, $sub, @args) = @_; - if (my $s1 = $self->{-ipc_sock}) { + if (my $w_req = $self->{-ipc_req}) { # run in worker my $ipc_lock = $self->{-ipc_lock}; my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef; - _send_rec($s1, [ wantarray, $sub, @args ]); - return unless defined(wantarray); - my $ret = _get_rec($s1) // die "no response on $sub"; - die $$ret if ref($ret) eq 'PublicInbox::IPC::Die'; - wantarray ? @$ret : $$ret; - } else { + if (defined(wantarray)) { + my $r_res = $self->{-ipc_res} or die 'no ipc_res'; + _send_rec($w_req, [ wantarray, $sub, @args ]); + my $ret = _get_rec($r_res) // die "no response on $sub"; + die $$ret if ref($ret) eq 'PublicInbox::IPC::Die'; + wantarray ? @$ret : $$ret; + } else { # likely, fire-and-forget into pipe + _send_rec($w_req, [ undef , $sub, @args ]); + } + } else { # run locally $self->$sub(@args); } } +# needed when there's multiple IPC workers and the parent forking +# causes newer siblings to inherit older siblings sockets +sub ipc_sibling_atfork_child { + my ($self) = @_; + my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)}); + delete(@$self{qw(-ipc_req -ipc_res)}); + $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself"; +} + 1; diff --git a/lib/PublicInbox/SearchIdxShard.pm b/lib/PublicInbox/SearchIdxShard.pm index 83cbbb25..0051df93 100644 --- a/lib/PublicInbox/SearchIdxShard.pm +++ b/lib/PublicInbox/SearchIdxShard.pm @@ -21,6 +21,14 @@ sub new { if ($v2w->{parallel}) { local $self->{-v2w_afc} = $v2w; $self->ipc_worker_spawn("shard[$shard]"); + # F_SETPIPE_SZ = 1031 on Linux; increasing the pipe size for + # inputs speeds V2Writable batch imports across 8 cores by + # nearly 20%. Since any of our responses are small, make + # the response pipe as small as possible + if ($^O eq 'linux') { + fcntl($self->{-ipc_req}, 1031, 1048576); + fcntl($self->{-ipc_res}, 1031, 4096); + } } $self; } @@ -36,7 +44,7 @@ sub _worker_done { sub ipc_atfork_child { # called automatically before ipc_worker_loop my ($self) = @_; my $v2w = delete $self->{-v2w_afc} or die 'BUG: {-v2w_afc} missing'; - $v2w->atfork_child; # calls shard_atfork_child on our siblings + $v2w->atfork_child; # calls ipc_sibling_atfork_child on our siblings $v2w->{current_info} = "[$self->{shard}]"; # for $SIG{__WARN__} $self->begin_txn_lazy; # caller must capture this: @@ -49,17 +57,6 @@ sub index_eml { $self->ipc_do('add_message', $eml, $smsg); } -# needed when there's multiple IPC workers and the parent forking -# causes newer siblings to inherit older siblings sockets -sub shard_atfork_child { - my ($self) = @_; - my $pid = delete($self->{-ipc_worker_pid}) or - die "BUG: $$ no -ipc_worker_pid"; - my $s1 = delete($self->{-ipc_sock}) or die "BUG: $$ no -ipc_sock"; - $pid == $$ and die "BUG: $$ shard_atfork_child called on itself"; - close($s1) or die "close -ipc_sock: $!"; -} - # wait for return to determine when ipc_do('commit_txn_lazy') is done sub echo { shift; @@ -80,7 +77,7 @@ sub shard_close { sub shard_over_check { my ($self, $over) = @_; - if ($self->{-ipc_sock} && $over->{dbh}) { + if ($self->{-ipc_req} && $over->{dbh}) { # can't send DB handles over IPC $over = ref($over)->new($over->{dbh}->sqlite_db_filename); } diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm index c4efbdd2..6be95979 100644 --- a/lib/PublicInbox/V2Writable.pm +++ b/lib/PublicInbox/V2Writable.pm @@ -823,7 +823,7 @@ sub content_exists ($$$) { 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;