libstdc++: Also use sendfile for big files

We were previously only using sendfile for files smaller than 2GB, as
sendfile needs to be called repeatedly for files bigger than that.

Some quick numbers, copying a 16GB file, average of 10 repetitions:
    old:
        real: 13.4s
        user: 0.14s
        sys : 7.43s
    new:
        real: 8.90s
        user: 0.00s
        sys : 3.68s

libstdc++-v3/ChangeLog:

	* acinclude.m4 (_GLIBCXX_HAVE_LSEEK): Define.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* src/filesystem/ops-common.h (copy_file_sendfile): Define new
	function for sendfile logic. Loop to support large files. Skip
	zero-length files.
	(do_copy_file): Use it.

Signed-off-by: Jannik Glückert <jannik.glueckert@gmail.com>

1 files changed, 91 insertions, 36 deletions

diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 70d169c..50a7c30 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -71005,29 +71005,27 @@ $as_echo "$glibcxx_cv_fchmodat" >&6; }
 $as_echo "#define _GLIBCXX_USE_FCHMODAT 1" >>confdefs.h
 
   fi
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for sendfile that can copy files" >&5
-$as_echo_n "checking for sendfile that can copy files... " >&6; }
-if ${glibcxx_cv_sendfile+:} false; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for link" >&5
+$as_echo_n "checking for link... " >&6; }
+if ${glibcxx_cv_link+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-      case "${target_os}" in
-      gnu* | linux* | solaris* | uclinux*)
-	if test x$gcc_no_link = xyes; then
+      if test x$gcc_no_link = xyes; then
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <sys/sendfile.h>
+#include <unistd.h>
 int
 main ()
 {
-sendfile(1, 2, (off_t*)0, sizeof 1);
+link("", "");
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_cxx_try_compile "$LINENO"; then :
-  glibcxx_cv_sendfile=yes
+  glibcxx_cv_link=yes
 else
-  glibcxx_cv_sendfile=no
+  glibcxx_cv_link=no
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
@@ -71036,40 +71034,35 @@ else
 fi
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <sys/sendfile.h>
+#include <unistd.h>
 int
 main ()
 {
-sendfile(1, 2, (off_t*)0, sizeof 1);
+link("", "");
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_cxx_try_link "$LINENO"; then :
-  glibcxx_cv_sendfile=yes
+  glibcxx_cv_link=yes
 else
-  glibcxx_cv_sendfile=no
+  glibcxx_cv_link=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 fi
-	;;
-      *)
-	glibcxx_cv_sendfile=no
-	;;
-    esac
 
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_sendfile" >&5
-$as_echo "$glibcxx_cv_sendfile" >&6; }
-  if test $glibcxx_cv_sendfile = yes; then
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_link" >&5
+$as_echo "$glibcxx_cv_link" >&6; }
+  if test $glibcxx_cv_link = yes; then
 
-$as_echo "#define _GLIBCXX_USE_SENDFILE 1" >>confdefs.h
+$as_echo "#define HAVE_LINK 1" >>confdefs.h
 
   fi
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for link" >&5
-$as_echo_n "checking for link... " >&6; }
-if ${glibcxx_cv_link+:} false; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for lseek" >&5
+$as_echo_n "checking for lseek... " >&6; }
+if ${glibcxx_cv_lseek+:} false; then :
   $as_echo_n "(cached) " >&6
 else
       if test x$gcc_no_link = xyes; then
@@ -71079,15 +71072,15 @@ else
 int
 main ()
 {
-link("", "");
+lseek(1, 0, SEEK_SET);
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_cxx_try_compile "$LINENO"; then :
-  glibcxx_cv_link=yes
+  glibcxx_cv_lseek=yes
 else
-  glibcxx_cv_link=no
+  glibcxx_cv_lseek=no
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
@@ -71100,26 +71093,26 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 int
 main ()
 {
-link("", "");
+lseek(1, 0, SEEK_SET);
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_cxx_try_link "$LINENO"; then :
-  glibcxx_cv_link=yes
+  glibcxx_cv_lseek=yes
 else
-  glibcxx_cv_link=no
+  glibcxx_cv_lseek=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 fi
 
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_link" >&5
-$as_echo "$glibcxx_cv_link" >&6; }
-  if test $glibcxx_cv_link = yes; then
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_lseek" >&5
+$as_echo "$glibcxx_cv_lseek" >&6; }
+  if test $glibcxx_cv_lseek = yes; then
 
-$as_echo "#define HAVE_LINK 1" >>confdefs.h
+$as_echo "#define HAVE_LSEEK 1" >>confdefs.h
 
   fi
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for readlink" >&5
@@ -71287,6 +71280,68 @@ $as_echo "$glibcxx_cv_truncate" >&6; }
 $as_echo "#define HAVE_TRUNCATE 1" >>confdefs.h
 
   fi
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for sendfile that can copy files" >&5
+$as_echo_n "checking for sendfile that can copy files... " >&6; }
+if ${glibcxx_cv_sendfile+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+      case "${target_os}" in
+      gnu* | linux* | solaris* | uclinux*)
+	if test x$gcc_no_link = xyes; then
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/sendfile.h>
+int
+main ()
+{
+sendfile(1, 2, (off_t*)0, sizeof 1);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  glibcxx_cv_sendfile=yes
+else
+  glibcxx_cv_sendfile=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+else
+  if test x$gcc_no_link = xyes; then
+  as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5
+fi
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/sendfile.h>
+int
+main ()
+{
+sendfile(1, 2, (off_t*)0, sizeof 1);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_link "$LINENO"; then :
+  glibcxx_cv_sendfile=yes
+else
+  glibcxx_cv_sendfile=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+	;;
+      *)
+	glibcxx_cv_sendfile=no
+	;;
+    esac
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_sendfile" >&5
+$as_echo "$glibcxx_cv_sendfile" >&6; }
+  if test $glibcxx_cv_sendfile = yes && test $glibcxx_cv_lseek = yes; then
+
+$as_echo "#define _GLIBCXX_USE_SENDFILE 1" >>confdefs.h
+
+  fi
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for fdopendir" >&5
 $as_echo_n "checking for fdopendir... " >&6; }
 if ${glibcxx_cv_fdopendir+:} false; then :