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Diffstat (limited to 'lib/PublicInbox/NNTPdeflate.pm')
-rw-r--r-- | lib/PublicInbox/NNTPdeflate.pm | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/PublicInbox/NNTPdeflate.pm b/lib/PublicInbox/NNTPdeflate.pm new file mode 100644 index 00000000..66210bfa --- /dev/null +++ b/lib/PublicInbox/NNTPdeflate.pm @@ -0,0 +1,104 @@ +# Copyright (C) 2019 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 +package PublicInbox::NNTPdeflate; +use strict; +use warnings; +use 5.010_001; +use base qw(PublicInbox::NNTP); +use Compress::Raw::Zlib; +use Hash::Util qw(unlock_hash); # dependency of fields for perl 5.10+, anyways + +my %IN_OPT = ( + -Bufsize => PublicInbox::NNTP::LINE_MAX, + -WindowBits => -15, # RFC 1951 + -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, + + -WindowBits => -15, # RFC 1951 + -AppendOutput => 1, +); + +sub enable { + my ($class, $self) = @_; + unlock_hash(%$self); + bless $self, $class; + $self->{zin} = [ Compress::Raw::Zlib::Inflate->new(%IN_OPT), '' ]; + $self->{zout} = [ Compress::Raw::Zlib::Deflate->new(%OUT_OPT), '' ]; +} + +# overrides PublicInbox::NNTP::compressed +sub compressed { 1 } + +# SUPER is PublicInbox::DS::do_read, so $_[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; + + # assert(length($$rbuf) == $off) as far as NNTP.pm is concerned + # -ConsumeInput is true, so $deflated is automatically emptied + my $err = $zin->[0]->inflate($deflated, $rbuf); + if ($err == Z_OK) { + $r = length($$rbuf) and return $r; + # nothing ready, yet, get more, later + $self->requeue; + } else { + delete $self->{zin}; + $self->close; + } + 0; +} + +# override PublicInbox::DS::msg_more +sub msg_more ($$) { + my $self = $_[0]; + my $zout = $self->{zout}; + + # $_[1] may be a reference or not for ->deflate + my $err = $zout->[0]->deflate($_[1], $zout->[1]); + $err == Z_OK or die "->deflate failed $err"; + 1; +} + +# SUPER is PublicInbox::DS::write, so $_[1] may be a reference or not +sub write ($$) { + my $self = $_[0]; + return $self->SUPER::write($_[1]) if ref($_[1]) eq 'CODE'; + my $zout = $self->{zout}; + my $deflated = pop @$zout; + + # $_[1] may be a reference or not for ->deflate + my $err = $zout->[0]->deflate($_[1], $deflated); + $err == Z_OK or die "->deflate failed $err"; + $err = $zout->[0]->flush($deflated, Z_PARTIAL_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); +} + +1; |