Inlining `scm_getc ()' and friends

[ludo@gnu.org (Ludovic Courtès)]

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Hello,

Small I/O functions like `scm_getc ()' deserve to be inlined.  For
instance, Andy measured it some time ago:

  http://thread.gmane.org/gmane.lisp.guile.devel/6639

I'm planning to apply the attached patch to both `master' and 1.8.

To get an idea of its benefit, I run the attached "benchmark" (inspired
from that in Guile-Reader) that does a lot of `read'.  On my 1.2 GHz
Intel Centrino, the inlining yields a 15% run-time improvement for that
test.

OK to apply?

Thanks,
Ludovic.


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[-- Attachment #2: The patch --]
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From 4eeedb81429859b683277eee3af38532ee02733f Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Mon, 14 Apr 2008 18:09:49 +0200
Subject: [PATCH] Inline `scm_getc', `scm_putc' and `scm_puts'.

---
 libguile/inline.h |   86 +++++++++++++++++++++++++++++++++++++++++++++++++---
 libguile/ports.c  |   60 +------------------------------------
 libguile/ports.h  |    5 +--
 3 files changed, 83 insertions(+), 68 deletions(-)

diff --git a/libguile/inline.h b/libguile/inline.h
index 8a6635e..8fa9a8c 100644
--- a/libguile/inline.h
+++ b/libguile/inline.h
@@ -25,17 +25,17 @@
    "inline.c".
 */
 
-#include "libguile/__scm.h"
-
-#if (SCM_DEBUG_CELL_ACCESSES == 1)
 #include <stdio.h>
-#endif
+#include <string.h>
+
+#include "libguile/__scm.h"
 
 #include "libguile/pairs.h"
 #include "libguile/gc.h"
 #include "libguile/threads.h"
 #include "libguile/unif.h"
-#include "libguile/pairs.h"
+#include "libguile/ports.h"
+#include "libguile/error.h"
 
 
 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
@@ -85,6 +85,10 @@ SCM_API void scm_array_handle_set (scm_t_array_handle *h, ssize_t pos, SCM val);
 
 SCM_API int scm_is_pair (SCM x);
 
+SCM_API int scm_getc (SCM port);
+SCM_API void scm_putc (char c, SCM port);
+SCM_API void scm_puts (const char *str_data, SCM port);
+
 #endif
 
 
@@ -285,5 +289,77 @@ scm_is_pair (SCM x)
   return SCM_I_CONSP (x);
 }
 
+
+/* Port I/O.  */
+
+#ifndef SCM_INLINE_C_INCLUDING_INLINE_H
+SCM_C_EXTERN_INLINE
+#endif
+int
+scm_getc (SCM port)
+{
+  int c;
+  scm_t_port *pt = SCM_PTAB_ENTRY (port);
+
+  if (pt->rw_active == SCM_PORT_WRITE)
+    /* may be marginally faster than calling scm_flush.  */
+    scm_ptobs[SCM_PTOBNUM (port)].flush (port);
+
+  if (pt->rw_random)
+    pt->rw_active = SCM_PORT_READ;
+
+  if (pt->read_pos >= pt->read_end)
+    {
+      if (scm_fill_input (port) == EOF)
+	return EOF;
+    }
+
+  c = *(pt->read_pos++);
+
+  switch (c)
+    {
+      case '\a':
+        break;
+      case '\b':
+        SCM_DECCOL (port);
+        break;
+      case '\n':
+        SCM_INCLINE (port);
+        break;
+      case '\r':
+        SCM_ZEROCOL (port);
+        break;
+      case '\t':
+        SCM_TABCOL (port);
+        break;
+      default:
+        SCM_INCCOL (port);
+        break;
+    }
+
+  return c;
+}
+
+#ifndef SCM_INLINE_C_INCLUDING_INLINE_H
+SCM_C_EXTERN_INLINE
+#endif
+void
+scm_putc (char c, SCM port)
+{
+  SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
+  scm_lfwrite (&c, 1, port);
+}
+
+#ifndef SCM_INLINE_C_INCLUDING_INLINE_H
+SCM_C_EXTERN_INLINE
+#endif
+void
+scm_puts (const char *s, SCM port)
+{
+  SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
+  scm_lfwrite (s, strlen (s), port);
+}
+
+
 #endif
 #endif
diff --git a/libguile/ports.c b/libguile/ports.c
index c4ccca3..b25a7d0 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -960,64 +960,6 @@ scm_fill_input (SCM port)
   return scm_ptobs[SCM_PTOBNUM (port)].fill_input (port);
 }
 
-int 
-scm_getc (SCM port)
-{
-  int c;
-  scm_t_port *pt = SCM_PTAB_ENTRY (port);
-
-  if (pt->rw_active == SCM_PORT_WRITE)
-    /* may be marginally faster than calling scm_flush.  */
-    scm_ptobs[SCM_PTOBNUM (port)].flush (port);
-  
-  if (pt->rw_random)
-    pt->rw_active = SCM_PORT_READ;
-
-  if (pt->read_pos >= pt->read_end)
-    {
-      if (scm_fill_input (port) == EOF)
-	return EOF;
-    }
-
-  c = *(pt->read_pos++);
-
-  switch (c)
-    {
-      case '\a':
-        break;
-      case '\b':
-        SCM_DECCOL (port);
-        break;
-      case '\n':
-        SCM_INCLINE (port);
-        break;
-      case '\r':
-        SCM_ZEROCOL (port);
-        break;
-      case '\t':
-        SCM_TABCOL (port);
-        break;
-      default:
-        SCM_INCCOL (port);
-        break;
-    }
- 
-  return c;
-}
-
-void 
-scm_putc (char c, SCM port)
-{
-  SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
-  scm_lfwrite (&c, 1, port);
-}
-
-void 
-scm_puts (const char *s, SCM port)
-{
-  SCM_ASSERT_TYPE (SCM_OPOUTPORTP (port), port, 0, NULL, "output port");
-  scm_lfwrite (s, strlen (s), port);
-}
 
 /* scm_lfwrite
  *
diff --git a/libguile/ports.h b/libguile/ports.h
index b93135e..fb0ef4e 100644
--- a/libguile/ports.h
+++ b/libguile/ports.h
@@ -3,7 +3,7 @@
 #ifndef SCM_PORTS_H
 #define SCM_PORTS_H
 
-/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2006, 2008 Free Software Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -264,15 +264,12 @@ SCM_API SCM scm_eof_object_p (SCM x);
 SCM_API SCM scm_force_output (SCM port);
 SCM_API SCM scm_flush_all_ports (void);
 SCM_API SCM scm_read_char (SCM port);
-SCM_API void scm_putc (char c, SCM port);
-SCM_API void scm_puts (const char *str_data, SCM port);
 SCM_API size_t scm_c_read (SCM port, void *buffer, size_t size);
 SCM_API void scm_c_write (SCM port, const void *buffer, size_t size);
 SCM_API void scm_lfwrite (const char *ptr, size_t size, SCM port);
 SCM_API void scm_flush (SCM port);
 SCM_API void scm_end_input (SCM port);
 SCM_API int scm_fill_input (SCM port);
-SCM_API int scm_getc (SCM port);
 SCM_API void scm_ungetc (int c, SCM port);
 SCM_API void scm_ungets (const char *s, int n, SCM port);
 SCM_API SCM scm_peek_char (SCM port);
-- 
1.5.5


[-- Attachment #3: The benchmark --]
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(define %files-to-load
  (map %search-load-path
       '("ice-9/boot-9.scm"  "ice-9/common-list.scm"
	 "ice-9/format.scm"  "ice-9/optargs.scm"
	 "ice-9/session.scm" "ice-9/getopt-long.scm"
         "ice-9/psyntax.pp")))

;; Number of iterations reading files.  Adjust this as a function of your
;; machine's CPU power.
(define %iterations 50)

(define (load-file-with-reader file-name reader)
  (with-input-from-file file-name
    (lambda ()
      (setvbuf (current-input-port) _IOFBF 4096)
      (let loop ((sexp (reader)))
        (if (eof-object? sexp)
            #t
	    (loop (reader)))))))

(define (how-long reader)

  ;; `get-internal-run-time' includes both system and user time.
  (define (time-elapsed) (tms:utime (times)))

  (let loop ((start (time-elapsed))
	     (iterations-left %iterations))
    (if (= 0 iterations-left)
	(- (time-elapsed) start)
	(begin
	  (for-each (lambda (file)
		      (load-file-with-reader file reader))
		    %files-to-load)
	  (loop start (- iterations-left 1))))))

(format #t "time elapsed: ~a~%"
        (how-long read))

;; Timing:
;;  master-with-inline-io: 161
;;  master:                191
;; => 15% improvement