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From: Eric Wong <e@80x24.org>
To: kgio-public@bogomips.org
Cc: Eric Wong <e@80x24.org>
Subject: [PATCH] remove autopush support and make it a no-op
Date: Thu, 13 Aug 2015 20:55:39 +0000	[thread overview]
Message-ID: <1439499339-29222-1-git-send-email-e@80x24.org> (raw)

Maintaining global state in a library like kgio is ugly, and it
is not optimal from a performance standpoint compared to using
MSG_MORE.

TCP_CORK and TCP_NOPUSH require extra syscalls so it still offers
sub-optimal performance compared to MSG_MORE.

Instead, server developers should use MSG_MORE if their OS supports
it (and should add MSG_MORE to their OS if lacking it).
---
 .document             |   1 -
 ext/kgio/accept.c     |   7 --
 ext/kgio/autopush.c   | 247 --------------------------------------------------
 ext/kgio/kgio.h       |  12 ---
 ext/kgio/kgio_ext.c   |   1 -
 ext/kgio/read.c       |   8 --
 ext/kgio/write.c      |   4 -
 ext/kgio/writev.c     |   2 -
 lib/kgio.rb           |  10 ++
 test/test_autopush.rb | 160 +-------------------------------
 10 files changed, 13 insertions(+), 439 deletions(-)
 delete mode 100644 ext/kgio/autopush.c

diff --git a/.document b/.document
index c7e09c6..f3a0872 100644
--- a/.document
+++ b/.document
@@ -7,7 +7,6 @@ ISSUES
 HACKING
 lib
 ext/kgio/accept.c
-ext/kgio/autopush.c
 ext/kgio/connect.c
 ext/kgio/kgio_ext.c
 ext/kgio/poll.c
diff --git a/ext/kgio/accept.c b/ext/kgio/accept.c
index c847c92..4a45e2f 100644
--- a/ext/kgio/accept.c
+++ b/ext/kgio/accept.c
@@ -160,12 +160,6 @@ static VALUE in_addr_set(VALUE io, struct sockaddr_storage *addr, socklen_t len)
 	return rb_ivar_set(io, iv_kgio_addr, host);
 }
 
-#if defined(__linux__)
-#  define post_accept kgio_autopush_accept
-#else
-#  define post_accept(a,b) for(;0;)
-#endif
-
 static VALUE
 my_accept(struct accept_args *a, int force_nonblock)
 {
@@ -211,7 +205,6 @@ retry:
 		}
 	}
 	client_io = sock_for_fd(a->accepted_class, client_fd);
-	post_accept(a->accept_io, client_io);
 
 	if (a->addr)
 		in_addr_set(client_io,
diff --git a/ext/kgio/autopush.c b/ext/kgio/autopush.c
deleted file mode 100644
index 74576e8..0000000
--- a/ext/kgio/autopush.c
+++ /dev/null
@@ -1,247 +0,0 @@
-/*
- * We use a very basic strategy to use TCP_CORK semantics optimally
- * in most TCP servers:  On corked sockets, we will uncork on recv()
- * if there was a previous send().  Otherwise we do not fiddle
- * with TCP_CORK at all.
- *
- * Under Linux, we can rely on TCP_CORK being inherited in an
- * accept()-ed client socket so we can avoid syscalls for each
- * accept()-ed client if we know the accept() socket corks.
- *
- * This module does NOTHING for client TCP sockets, we only deal
- * with accept()-ed sockets right now.
- */
-
-#include "kgio.h"
-#include "my_fileno.h"
-#include <netinet/tcp.h>
-
-/*
- * As of FreeBSD 4.5, TCP_NOPUSH == TCP_CORK
- * ref: http://dotat.at/writing/nopush.html
- * We won't care for older FreeBSD since nobody runs Ruby on them...
- */
-#ifdef TCP_CORK
-#  define KGIO_NOPUSH TCP_CORK
-#elif defined(TCP_NOPUSH)
-#  define KGIO_NOPUSH TCP_NOPUSH
-#endif
-
-#ifdef KGIO_NOPUSH
-static ID id_autopush_state;
-static int enabled = 1;
-
-enum autopush_state {
-	AUTOPUSH_STATE_ACCEPTOR_IGNORE = -1,
-	AUTOPUSH_STATE_IGNORE = 0,
-	AUTOPUSH_STATE_WRITER = 1,
-	AUTOPUSH_STATE_WRITTEN = 2,
-	AUTOPUSH_STATE_ACCEPTOR = 3
-};
-
-#if defined(R_CAST) && \
-    defined(HAVE_TYPE_STRUCT_RFILE) && \
-    defined(HAVE_TYPE_STRUCT_ROBJECT) && \
-    ((SIZEOF_STRUCT_RFILE + SIZEOF_INT) <= (SIZEOF_STRUCT_ROBJECT))
-
-struct AutopushSocket {
-	struct RFile rfile;
-	enum autopush_state autopush_state;
-};
-
-static enum autopush_state state_get(VALUE io)
-{
-	return ((struct AutopushSocket *)(io))->autopush_state;
-}
-
-static void state_set(VALUE io, enum autopush_state state)
-{
-	((struct AutopushSocket *)(io))->autopush_state = state;
-}
-#else
-static enum autopush_state state_get(VALUE io)
-{
-	VALUE val;
-
-	if (rb_ivar_defined(io, id_autopush_state) == Qfalse)
-		return AUTOPUSH_STATE_IGNORE;
-	val = rb_ivar_get(io, id_autopush_state);
-
-	return (enum autopush_state)NUM2INT(val);
-}
-
-static void state_set(VALUE io, enum autopush_state state)
-{
-	rb_ivar_set(io, id_autopush_state, INT2NUM(state));
-}
-#endif /* IVAR fallback */
-
-static enum autopush_state detect_acceptor_state(VALUE io);
-static void push_pending_data(VALUE io);
-
-/*
- * call-seq:
- *	Kgio.autopush? -> true or false
- *
- * Returns whether or not autopush is enabled.
- *
- * Only available on systems with TCP_CORK (Linux) or
- * TCP_NOPUSH (FreeBSD, and maybe other *BSDs).
- */
-static VALUE s_get_autopush(VALUE self)
-{
-	return enabled ? Qtrue : Qfalse;
-}
-
-/*
- * call-seq:
- *	Kgio.autopush = true
- *	Kgio.autopush = false
- *
- * Enables or disables autopush for sockets created with kgio_accept
- * and kgio_tryaccept methods.  Autopush relies on TCP_CORK/TCP_NOPUSH
- * being enabled on the listen socket.
- *
- * Only available on systems with TCP_CORK (Linux) or
- * TCP_NOPUSH (FreeBSD, and maybe other *BSDs).
- */
-static VALUE s_set_autopush(VALUE self, VALUE val)
-{
-	enabled = RTEST(val);
-
-	return val;
-}
-
-/*
- * call-seq:
- *
- *	io.kgio_autopush?  -> true or false
- *
- * Returns the current autopush state of the Kgio::SocketMethods-enabled
- * socket.
- *
- * Only available on systems with TCP_CORK (Linux) or
- * TCP_NOPUSH (FreeBSD, and maybe other *BSDs).
- */
-static VALUE autopush_get(VALUE io)
-{
-	return state_get(io) <= 0 ? Qfalse : Qtrue;
-}
-
-/*
- * call-seq:
- *
- *	io.kgio_autopush = true
- *	io.kgio_autopush = false
- *
- * Enables or disables autopush on any given Kgio::SocketMethods-capable
- * IO object.  This does NOT enable or disable TCP_NOPUSH/TCP_CORK right
- * away, that must be done with IO.setsockopt
- *
- * Only available on systems with TCP_CORK (Linux) or
- * TCP_NOPUSH (FreeBSD, and maybe other *BSDs).
- */
-static VALUE autopush_set(VALUE io, VALUE vbool)
-{
-	if (RTEST(vbool))
-		state_set(io, AUTOPUSH_STATE_WRITER);
-	else
-		state_set(io, AUTOPUSH_STATE_IGNORE);
-	return vbool;
-}
-
-void init_kgio_autopush(void)
-{
-	VALUE mKgio = rb_define_module("Kgio");
-	VALUE tmp;
-
-	rb_define_singleton_method(mKgio, "autopush?", s_get_autopush, 0);
-	rb_define_singleton_method(mKgio, "autopush=", s_set_autopush, 1);
-
-	tmp = rb_define_module_under(mKgio, "SocketMethods");
-	rb_define_method(tmp, "kgio_autopush=", autopush_set, 1);
-	rb_define_method(tmp, "kgio_autopush?", autopush_get, 0);
-
-	id_autopush_state = rb_intern("@kgio_autopush_state");
-}
-
-/*
- * called after a successful write, just mark that we've put something
- * in the skb and will need to uncork on the next write.
- */
-void kgio_autopush_send(VALUE io)
-{
-	if (state_get(io) == AUTOPUSH_STATE_WRITER)
-		state_set(io, AUTOPUSH_STATE_WRITTEN);
-}
-
-/* called on successful accept() */
-void kgio_autopush_accept(VALUE accept_io, VALUE client_io)
-{
-	enum autopush_state acceptor_state;
-
-	if (!enabled)
-		return;
-	acceptor_state = state_get(accept_io);
-	if (acceptor_state == AUTOPUSH_STATE_IGNORE)
-		acceptor_state = detect_acceptor_state(accept_io);
-	if (acceptor_state == AUTOPUSH_STATE_ACCEPTOR)
-		state_set(client_io, AUTOPUSH_STATE_WRITER);
-	else
-		state_set(client_io, AUTOPUSH_STATE_IGNORE);
-}
-
-void kgio_autopush_recv(VALUE io)
-{
-	if (enabled && (state_get(io) == AUTOPUSH_STATE_WRITTEN)) {
-		push_pending_data(io);
-		state_set(io, AUTOPUSH_STATE_WRITER);
-	}
-}
-
-static enum autopush_state detect_acceptor_state(VALUE io)
-{
-	int corked = 0;
-	int fd = my_fileno(io);
-	socklen_t optlen = sizeof(int);
-	enum autopush_state state;
-
-	if (getsockopt(fd, IPPROTO_TCP, KGIO_NOPUSH, &corked, &optlen) != 0) {
-		if (errno != EOPNOTSUPP)
-			rb_sys_fail("getsockopt(TCP_CORK/TCP_NOPUSH)");
-		errno = 0;
-		state = AUTOPUSH_STATE_ACCEPTOR_IGNORE;
-	} else if (corked) {
-		state = AUTOPUSH_STATE_ACCEPTOR;
-	} else {
-		state = AUTOPUSH_STATE_ACCEPTOR_IGNORE;
-	}
-	state_set(io, state);
-
-	return state;
-}
-
-/*
- * checks to see if we've written anything since the last recv()
- * If we have, uncork the socket and immediately recork it.
- */
-static void push_pending_data(VALUE io)
-{
-	int optval = 0;
-	const socklen_t optlen = sizeof(int);
-	const int fd = my_fileno(io);
-
-	if (setsockopt(fd, IPPROTO_TCP, KGIO_NOPUSH, &optval, optlen) != 0)
-		rb_sys_fail("setsockopt(TCP_CORK/TCP_NOPUSH, 0)");
-	/* immediately recork */
-	optval = 1;
-	if (setsockopt(fd, IPPROTO_TCP, KGIO_NOPUSH, &optval, optlen) != 0)
-		rb_sys_fail("setsockopt(TCP_CORK/TCP_NOPUSH, 1)");
-}
-#else /* !KGIO_NOPUSH */
-void kgio_autopush_recv(VALUE io){}
-void kgio_autopush_send(VALUE io){}
-void init_kgio_autopush(void)
-{
-}
-#endif /* ! KGIO_NOPUSH */
diff --git a/ext/kgio/kgio.h b/ext/kgio/kgio.h
index c0630ae..a3f2f66 100644
--- a/ext/kgio/kgio.h
+++ b/ext/kgio/kgio.h
@@ -29,14 +29,9 @@ void init_kgio_write(void);
 void init_kgio_writev(void);
 void init_kgio_accept(void);
 void init_kgio_connect(void);
-void init_kgio_autopush(void);
 void init_kgio_poll(void);
 void init_kgio_tryopen(void);
 
-void kgio_autopush_accept(VALUE, VALUE);
-void kgio_autopush_recv(VALUE);
-void kgio_autopush_send(VALUE);
-
 VALUE kgio_call_wait_writable(VALUE io);
 VALUE kgio_call_wait_readable(VALUE io);
 #if defined(HAVE_RB_THREAD_CALL_WITHOUT_GVL) && defined(HAVE_RUBY_THREAD_H)
@@ -90,13 +85,6 @@ NORETURN(void kgio_rd_sys_fail(const char *));
 #    define USE_MSG_DONTWAIT
 #  endif
 
-#ifdef USE_MSG_DONTWAIT
-/* we don't need these variants, we call kgio_autopush_send/recv directly */
-static inline void kgio_autopush_write(VALUE io) { }
-#else
-static inline void kgio_autopush_write(VALUE io) { kgio_autopush_send(io); }
-#endif
-
 /* prefer rb_str_subseq because we don't use negative offsets */
 #ifndef HAVE_RB_STR_SUBSEQ
 #define MY_STR_SUBSEQ(str,beg,len) rb_str_substr((str),(beg),(len))
diff --git a/ext/kgio/kgio_ext.c b/ext/kgio/kgio_ext.c
index 8829eae..c3e59ec 100644
--- a/ext/kgio/kgio_ext.c
+++ b/ext/kgio/kgio_ext.c
@@ -95,7 +95,6 @@ void Init_kgio_ext(void)
 	init_kgio_writev();
 	init_kgio_connect();
 	init_kgio_accept();
-	init_kgio_autopush();
 	init_kgio_poll();
 	init_kgio_tryopen();
 }
diff --git a/ext/kgio/read.c b/ext/kgio/read.c
index 472a592..e55db16 100644
--- a/ext/kgio/read.c
+++ b/ext/kgio/read.c
@@ -7,13 +7,8 @@ static VALUE sym_wait_readable;
 
 #ifdef USE_MSG_DONTWAIT
 static const int peek_flags = MSG_DONTWAIT|MSG_PEEK;
-
-/* we don't need these variants, we call kgio_autopush_recv directly */
-static inline void kgio_autopush_read(VALUE io) { }
-
 #else
 static const int peek_flags = MSG_PEEK;
-static inline void kgio_autopush_read(VALUE io) { kgio_autopush_recv(io); }
 #endif
 
 struct rd_args {
@@ -85,7 +80,6 @@ static VALUE my_read(int io_wait, int argc, VALUE *argv, VALUE io)
 	long n;
 
 	prepare_read(&a, argc, argv, io);
-	kgio_autopush_read(io);
 
 	if (a.len > 0) {
 		set_nonblocking(a.fd);
@@ -158,7 +152,6 @@ static VALUE my_recv(int io_wait, int argc, VALUE *argv, VALUE io)
 	long n;
 
 	prepare_read(&a, argc, argv, io);
-	kgio_autopush_recv(io);
 
 	if (a.len > 0) {
 retry:
@@ -212,7 +205,6 @@ static VALUE my_peek(int io_wait, int argc, VALUE *argv, VALUE io)
 	long n;
 
 	prepare_read(&a, argc, argv, io);
-	kgio_autopush_recv(io);
 
 	if (a.len > 0) {
 		if (peek_flags == MSG_PEEK)
diff --git a/ext/kgio/write.c b/ext/kgio/write.c
index ce4aa75..fa0d53c 100644
--- a/ext/kgio/write.c
+++ b/ext/kgio/write.c
@@ -72,8 +72,6 @@ retry:
 	n = (long)write(a.fd, a.ptr, a.len);
 	if (write_check(&a, n, "write", io_wait) != 0)
 		goto retry;
-	if (TYPE(a.buf) != T_SYMBOL)
-		kgio_autopush_write(io);
 	return a.buf;
 }
 
@@ -126,8 +124,6 @@ retry:
 	n = (long)send(a.fd, a.ptr, a.len, MSG_DONTWAIT);
 	if (write_check(&a, n, "send", io_wait) != 0)
 		goto retry;
-	if (TYPE(a.buf) != T_SYMBOL)
-		kgio_autopush_send(io);
 	return a.buf;
 }
 
diff --git a/ext/kgio/writev.c b/ext/kgio/writev.c
index d3ec53e..736aa6f 100644
--- a/ext/kgio/writev.c
+++ b/ext/kgio/writev.c
@@ -249,8 +249,6 @@ static VALUE my_writev(VALUE io, VALUE ary, int io_wait)
 	} while (writev_check(&a, n, "writev", io_wait) != 0);
 	rb_str_resize(a.vec_buf, 0);
 
-	if (TYPE(a.buf) != T_SYMBOL)
-		kgio_autopush_write(io);
 	return a.buf;
 }
 
diff --git a/lib/kgio.rb b/lib/kgio.rb
index 5de431b..f192074 100644
--- a/lib/kgio.rb
+++ b/lib/kgio.rb
@@ -16,6 +16,16 @@ module Kgio
   # PipeMethods#kgio_trywrite and SocketMethods#kgio_trywrite will return
   # :wait_writable when waiting for a read is required.
   WaitWritable = :wait_writable
+
+  # autopush is no-op nowadays
+  @autopush = false
+
+  class << self
+    attr_accessor :autopush # :nodoc:
+    def autopush? # :nodoc:
+      !!@autopush
+    end
+  end
 end
 
 require 'kgio_ext'
diff --git a/test/test_autopush.rb b/test/test_autopush.rb
index 38b7c52..4e5af92 100644
--- a/test/test_autopush.rb
+++ b/test/test_autopush.rb
@@ -1,165 +1,11 @@
-require 'tempfile'
 require 'test/unit'
-begin
-  $-w = false
-  RUBY_PLATFORM =~ /linux/ and require 'strace'
-rescue LoadError
-end
-$-w = true
 require 'kgio'
 
 class TestAutopush < Test::Unit::TestCase
-  TCP_CORK = 3
-  TCP_NOPUSH = 4
-
-  def setup
-    Kgio.autopush = false
-    assert_equal false, Kgio.autopush?
-
-    @host = ENV["TEST_HOST"] || '127.0.0.1'
-    @srv = Kgio::TCPServer.new(@host, 0)
-    RUBY_PLATFORM =~ /linux/ and
-      @srv.setsockopt(Socket::IPPROTO_TCP, TCP_CORK, 1)
-    RUBY_PLATFORM =~ /freebsd/ and
-      @srv.setsockopt(Socket::IPPROTO_TCP, TCP_NOPUSH, 1)
-    @port = @srv.addr[1]
-  end
-
-  def test_autopush_accessors
-    Kgio.autopush = true
-    opt = RUBY_PLATFORM =~ /freebsd/ ? TCP_NOPUSH : TCP_CORK
-    s = Kgio::TCPSocket.new(@host, @port)
-    assert_equal 0, s.getsockopt(Socket::IPPROTO_TCP, opt).unpack('i')[0]
-    assert ! s.kgio_autopush?
-    s.kgio_autopush = true
-    assert s.kgio_autopush?
-    s.kgio_write 'asdf'
-    assert_equal :wait_readable, s.kgio_tryread(1)
-    assert s.kgio_autopush?
-    val = s.getsockopt(Socket::IPPROTO_TCP, opt).unpack('i')[0]
-    assert_operator val, :>, 0, "#{opt}=#{val} (#{RUBY_PLATFORM})"
-  end
-
-  def test_autopush_true_unix
-    Kgio.autopush = true
-    tmp = Tempfile.new('kgio_unix')
-    @path = tmp.path
-    tmp.close!
-    @srv = Kgio::UNIXServer.new(@path)
-    @rd = Kgio::UNIXSocket.new(@path)
-    t0 = nil
-    if defined?(Strace)
-      io, err = Strace.me { @wr = @srv.kgio_accept }
-      assert_nil err
-      rc = nil
-      io, err = Strace.me {
-        t0 = Time.now
-        @wr.kgio_write "HI\n"
-        rc = @wr.kgio_tryread 666
-      }
-      assert_nil err
-      lines = io.readlines
-      assert lines.grep(/TCP_CORK/).empty?, lines.inspect
-    else
-      @wr = @srv.kgio_accept
-      t0 = Time.now
-      @wr.kgio_write "HI\n"
-      rc = @wr.kgio_tryread 666
-    end
-    assert_equal "HI\n", @rd.kgio_read(3)
-    diff = Time.now - t0
-    assert(diff < 0.200, "nopush on UNIX sockets? diff=#{diff} > 200ms")
-    assert_equal :wait_readable, rc
-  ensure
-    File.unlink(@path) rescue nil
-  end
-
-  def test_autopush_false
-    Kgio.autopush = nil
-    assert_equal false, Kgio.autopush?
-
-    @wr = Kgio::TCPSocket.new(@host, @port)
-    if defined?(Strace)
-      io, err = Strace.me { @rd = @srv.kgio_accept }
-      assert_nil err
-      lines = io.readlines
-      assert lines.grep(/TCP_CORK/).empty?, lines.inspect
-      assert_equal 1, @rd.getsockopt(Socket::SOL_TCP, TCP_CORK).unpack("i")[0]
-    else
-      @rd = @srv.kgio_accept
-    end
-
-    rbuf = "..."
-    t0 = Time.now
-    @rd.kgio_write "HI\n"
-    @wr.kgio_read(3, rbuf)
-    diff = Time.now - t0
-    assert(diff >= 0.190, "nopush broken? diff=#{diff} > 200ms")
-    assert_equal "HI\n", rbuf
-  end
-
-  def test_autopush_true
+  def test_compatibility
     Kgio.autopush = true
     assert_equal true, Kgio.autopush?
-    @wr = Kgio::TCPSocket.new(@host, @port)
-
-    if defined?(Strace)
-      io, err = Strace.me { @rd = @srv.kgio_accept }
-      assert_nil err
-      lines = io.readlines
-      assert_equal 1, lines.grep(/TCP_CORK/).size, lines.inspect
-      assert_equal 1, @rd.getsockopt(Socket::SOL_TCP, TCP_CORK).unpack("i")[0]
-    else
-      @rd = @srv.kgio_accept
-    end
-
-    @wr.write "HI\n"
-    rbuf = ""
-    if defined?(Strace)
-      io, err = Strace.me { @rd.kgio_read(3, rbuf) }
-      assert_nil err
-      lines = io.readlines
-      assert lines.grep(/TCP_CORK/).empty?, lines.inspect
-      assert_equal "HI\n", rbuf
-    else
-      assert_equal "HI\n", @rd.kgio_read(3, rbuf)
-    end
-
-    t0 = Time.now
-    @rd.kgio_write "HI2U2\n"
-    @rd.kgio_write "HOW\n"
-    rc = false
-
-    if defined?(Strace)
-      io, err = Strace.me { rc = @rd.kgio_tryread(666) }
-    else
-      rc = @rd.kgio_tryread(666)
-    end
-
-    @wr.readpartial(666, rbuf)
-    rbuf == "HI2U2\nHOW\n" or warn "rbuf=#{rbuf.inspect} looking bad?"
-    diff = Time.now - t0
-    assert(diff < 0.200, "time diff=#{diff} >= 200ms")
-    assert_equal :wait_readable, rc
-    if defined?(Strace)
-      assert_nil err
-      lines = io.readlines
-      assert_equal 2, lines.grep(/TCP_CORK/).size, lines.inspect
-    end
-    @wr.close
-    @rd.close
-
-    @wr = Kgio::TCPSocket.new(@host, @port)
-    if defined?(Strace)
-      io, err = Strace.me { @rd = @srv.kgio_accept }
-      assert_nil err
-      lines = io.readlines
-      assert lines.grep(/TCP_CORK/).empty?,"optimization fail: #{lines.inspect}"
-      assert_equal 1, @rd.getsockopt(Socket::SOL_TCP, TCP_CORK).unpack("i")[0]
-    end
-  end
-
-  def teardown
     Kgio.autopush = false
+    assert_equal false, Kgio.autopush?
   end
-end if RUBY_PLATFORM =~ /linux|freebsd/
+end
-- 
EW


             reply	other threads:[~2015-08-13 20:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-13 20:55 Eric Wong [this message]
2016-12-15 22:50 ` [PATCH] remove autopush support and make it a no-op Eric Wong
2016-12-16  0:01   ` [PUSHED] reinstate the original (and dangerous) autopush in C Eric Wong

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