psgi_rproxy: standardize on 64K I/O size

Much of our bulk I/O in DS and IO.pm already uses 64K buffers
(matching the Linux default pipe size) instead of 16K buffers.
While larger I/O sizes can result in more work for the malloc
implementation, they can also reduce syscall and Perl function
call overhead to reduce CPU usage and improve throughput on long
fat networks (LFNs).  Furthermore, standardizing on larger sizes
ought to reduce fragmentation since malloc can avoid splitting
existing buffers used for bulk I/O we do in other places.

diff --git a/lib/PublicInbox/H1ReqRes.pm b/lib/PublicInbox/H1ReqRes.pm
index bb68bcf3b0afb891a8eb6194fe61feb16cf517ae..8f49b45b634bb3c22647b85ad3c1cda6433ee23e 100644 (file)
--- a/lib/PublicInbox/H1ReqRes.pm
+++ b/lib/PublicInbox/H1ReqRes.pm
@@ -18,6 +18,7 @@ use constant { # duplicated from HTTP.pm
        CHUNK_END => -2,     # \r\n
        CHUNK_TLR_END => -3, # (trailers*)?\r\n
        CHUNK_MAX_HDR => 256,
+       IO_SIZE => 1 << 16,
 };
 
 sub new {
@@ -176,7 +177,7 @@ sub pass_res_chunked ($) {
                                        \n)* \r\n)//ismx) {
                                return pass_trailers $self, $1;
                        }
-                       die 'chunk not terminated' if length($$rbuf) > 0x4000;
+                       die 'chunk not terminated' if length($$rbuf) > IO_SIZE;
                }
                if ($len == CHUNK_END) {
                        if ($$rbuf =~ s/\A\r\n//s) {
@@ -196,7 +197,7 @@ sub pass_res_chunked ($) {
                        } # else break from loop since $len >= 0
                }
                if ($len < 0) {
-                       pass_refill($self, 0x4000, \&pass_res_chunked, $len) or
+                       pass_refill($self, IO_SIZE, \&pass_res_chunked, $len) or
                                return;
                        # (implicit) goto chunk_start if $r > 0;
                }
@@ -216,7 +217,7 @@ sub pass_res_chunked ($) {
                        }
                        if ($$rbuf eq '') {
                                # read more of current chunk
-                               pass_refill($self, 0x4000,
+                               pass_refill($self, IO_SIZE,
                                        \&pass_res_chunked, $len) or return;
                        }
                }
@@ -232,7 +233,7 @@ sub pass_res_identity ($) {
                        $len = _pass_res_block($self, $len) // return;
                }
                if ($$rbuf eq '' && $len) {
-                       my $n = $len > 0x4000 ? 0x4000 : $len;
+                       my $n = $len > IO_SIZE ? IO_SIZE : $len;
                        pass_refill($self, $n, \&pass_res_identity, $len) or
                                return;
                }
@@ -250,7 +251,7 @@ sub pass_res_until_eof ($) { # HTTP/1.0-only
                        $$rbuf = '';
                }
                if ($$rbuf eq '') {
-                       my $r = pass_refill($self, 0x4000,
+                       my $r = pass_refill($self, IO_SIZE,
                                        \&pass_res_until_eof, undef) // return;
                        last if $r == 0; # done
                }
@@ -262,7 +263,7 @@ sub pass_res_hdr ($) { # called by flush_write
        my ($self) = @_;
        my ($rbuf, $r, $code, $phdr);
        $rbuf = $self->{rbuf} // do {
-               $self->do_read(\(my $buf = ''), 0x4000) or
+               $self->do_read(\(my $buf = ''), IO_SIZE) or
                        return read_err $self, \&pass_res_hdr;
                $self->{rbuf} = \$buf;
        };
@@ -273,7 +274,7 @@ sub pass_res_hdr ($) { # called by flush_write
                if ($r == -2) { # incomplete
                        length($$rbuf) > 0x4000 and
                                die 'upstream response headers too large';
-                       $self->do_read($rbuf, 8192, length($$rbuf)) or return
+                       $self->do_read($rbuf, IO_SIZE, length($$rbuf)) or return
                                read_err $self, \&pass_res_hdr;
                } else {
                        die "upstream sent bad response headers (r=$r)";
@@ -342,7 +343,7 @@ sub send_req_body { # called by flush_write
        # n.b. PublicInbox::HTTP always reads the entire request body
        # before dispatching the PSGI app
        my $r = $self->{req_left};
-       $r = 0x4000 if $r > 0x4000;
+       $r = IO_SIZE if $r > IO_SIZE;
        $r = $self->{env}->{'psgi.input'}->read(my $buf, $r) //
                        die "input->read: $! ($self->{req_left} bytes left)";
        die "input->read: EOF ($self->{req_left} bytes left)" if $r == 0;