-# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# Copyright (C) 2019-2020 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# RFC 8054 NNTP COMPRESS DEFLATE implementation
-# Warning, enabling compression for C10K NNTP clients is rather
-# expensive in terms of memory use.
#
# RSS usage for 10K idle-but-did-something NNTP clients on 64-bit:
-# TLS + DEFLATE : 1.8 GB (MemLevel=9, 1.2 GB with MemLevel=8)
-# TLS only : <200MB
-# plain : <50MB
+# TLS + DEFLATE[a] : 1.8 GB (MemLevel=9, 1.2 GB with MemLevel=8)
+# TLS + DEFLATE[b] : ~300MB
+# TLS only : <200MB
+# plain : <50MB
+#
+# [a] - initial implementation using per-client Deflate contexts and buffer
+#
+# [b] - memory-optimized implementation using a global deflate context.
+# It's less efficient in terms of compression, but way more
+# efficient in terms of server memory usage.
package PublicInbox::NNTPdeflate;
use strict;
use warnings;
-AppendOutput => 1,
);
-my %OUT_OPT = (
- # nnrpd (INN) and Compress::Raw::Zlib favor MemLevel=9,
- # but the zlib C library and git use MemLevel=8
- # as the default. Using 8 drops our memory use with 10K
- # TLS clients from 1.8 GB to 1.2 GB, but...
- # FIXME: sometimes clients fail with 8, so we use 9
- # -MemLevel => 9,
-
- # needs more testing, nothing obviously different in terms of memory
- -Bufsize => 65536,
+# global deflate context and buffer
+my $zbuf = \(my $buf = '');
+my $zout;
+{
+ my $err;
+ ($zout, $err) = Compress::Raw::Zlib::Deflate->new(
+ # nnrpd (INN) and Compress::Raw::Zlib favor MemLevel=9,
+ # the zlib C library and git use MemLevel=8 as the default
+ # -MemLevel => 9,
+ -Bufsize => 65536, # same as nnrpd
+ -WindowBits => -15, # RFC 1951
+ -AppendOutput => 1,
+ );
+ $err == Z_OK or die "Failed to initialize zlib deflate stream: $err";
+}
- -WindowBits => -15, # RFC 1951
- -AppendOutput => 1,
-);
sub enable {
my ($class, $self) = @_;
+ my ($in, $err) = Compress::Raw::Zlib::Inflate->new(%IN_OPT);
+ if ($err != Z_OK) {
+ $self->err("Inflate->new failed: $err");
+ $self->res('403 Unable to activate compression');
+ return;
+ }
unlock_hash(%$self);
+ $self->res('206 Compression active');
bless $self, $class;
- $self->{zin} = [ Compress::Raw::Zlib::Inflate->new(%IN_OPT), '' ];
- $self->{zout} = [ Compress::Raw::Zlib::Deflate->new(%OUT_OPT), '' ];
+ $self->{zin} = $in;
}
# overrides PublicInbox::NNTP::compressed
sub compressed { 1 }
-# SUPER is PublicInbox::DS::do_read, so $_[1] may be a reference or not
+# $_[1] may be a reference or not
sub do_read ($$$$) {
my ($self, $rbuf, $len, $off) = @_;
my $zin = $self->{zin} or return; # closed
- my $deflated = \($zin->[1]);
- my $r = $self->SUPER::do_read($deflated, $len) or return;
+ my $doff;
+ my $dbuf = delete($self->{dbuf}) // '';
+ $doff = length($dbuf);
+ my $r = PublicInbox::DS::do_read($self, \$dbuf, $len, $doff) or return;
# assert(length($$rbuf) == $off) as far as NNTP.pm is concerned
- # -ConsumeInput is true, so $deflated is automatically emptied
- my $err = $zin->[0]->inflate($deflated, $rbuf);
+ # -ConsumeInput is true, so $dbuf is automatically emptied
+ my $err = $zin->inflate($dbuf, $rbuf);
if ($err == Z_OK) {
+ $self->{dbuf} = $dbuf if $dbuf ne '';
$r = length($$rbuf) and return $r;
# nothing ready, yet, get more, later
$self->requeue;
# override PublicInbox::DS::msg_more
sub msg_more ($$) {
my $self = $_[0];
- my $zout = $self->{zout};
# $_[1] may be a reference or not for ->deflate
- my $err = $zout->[0]->deflate($_[1], $zout->[1]);
+ my $err = $zout->deflate($_[1], $zbuf);
$err == Z_OK or die "->deflate failed $err";
1;
}
-# SUPER is PublicInbox::DS::write, so $_[1] may be a reference or not
+sub zflush ($) {
+ my ($self) = @_;
+
+ my $deflated = $zbuf;
+ $zbuf = \(my $next = '');
+
+ my $err = $zout->flush($deflated, Z_FULL_FLUSH);
+ $err == Z_OK or die "->flush failed $err";
+
+ # We can still let the lower socket layer do buffering:
+ PublicInbox::DS::msg_more($self, $$deflated);
+}
+
+# compatible with PublicInbox::DS::write, so $_[1] may be a reference or not
sub write ($$) {
my $self = $_[0];
- return $self->SUPER::write($_[1]) if ref($_[1]) eq 'CODE';
- my $zout = $self->{zout};
- my $deflated = pop @$zout;
+ return PublicInbox::DS::write($self, $_[1]) if ref($_[1]) eq 'CODE';
+
+ my $deflated = $zbuf;
+ $zbuf = \(my $next = '');
# $_[1] may be a reference or not for ->deflate
- my $err = $zout->[0]->deflate($_[1], $deflated);
+ my $err = $zout->deflate($_[1], $deflated);
$err == Z_OK or die "->deflate failed $err";
- $err = $zout->[0]->flush($deflated, Z_PARTIAL_FLUSH);
+ $err = $zout->flush($deflated, Z_FULL_FLUSH);
$err == Z_OK or die "->flush failed $err";
- # PublicInbox::DS::write puts partial writes into another buffer,
- # so we can prepare the next deflate buffer:
- $zout->[1] = '';
- $self->SUPER::write(\$deflated);
+ # We can still let the socket layer do buffering:
+ PublicInbox::DS::write($self, $deflated);
}
1;