Add benchmark tests for slowpow and slowexp

Separate benchmarks for the fast and slow implementations of pow and
exp since measuring both together doesn't make sense.  Adjust the
iterations for pow and exp accordingly so that they run long enough
for the measurements to be meaningful.

ChangeLog

@@ -1,3 +1,16 @@
+2013-04-02  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	* benchtests/Makefile: Add benchmarks for slowpow and slowexp.
+	(bench): Add slowexp and slowpow.
+	(exp-ITER): Increase iterations.
+	(pow-ITER): Likewise.
+	* benchtests/exp-inputs: Change input.
+	* benchtests/pow-inputs: Likewise.
+	* benchtests/slowexp-inputs: New file.
+	* benchtests/slowexp.c: New file.
+	* benchtests/slowpow-inputs: New file.
+	* benchtests/slowpow.c: New file.
+
 2013-04-02  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/powerpc32/fpu/s_rint.S: Remove branch prediction

benchtests/Makefile

@@ -25,7 +25,9 @@
 
 # - Define foo-ITER with the number of iterations you want to run.  Keep it
 #   high enough that the overhead of clock_gettime is only a small fraction of
-#   the total run time of the test.
+#   the total run time of the test.  A good idea would be to keep the run time
+#   of each test at around 10 seconds for x86_64.  That is just a guideline,
+#   since some scenarios may require higher run times.
 
 # - Define foo-ARGLIST as a colon separated list of types of the input
 #   arguments.  Use `void` if function does not take any inputs.  Put in quotes
@@ -43,14 +45,16 @@
 #   See pow-inputs for an example.
 
 subdir := benchtests
-bench := exp pow rint
+bench := exp pow rint slowexp slowpow
 
-exp-ITER = 100000
+# exp function fast path
+exp-ITER = 5e8
 exp-ARGLIST = double
 exp-RET = double
 LDFLAGS-bench-exp = -lm
 
-pow-ITER = 100000
+# pow function fast path
+pow-ITER = 2e8
 pow-ARGLIST = double:double
 pow-RET = double
 LDFLAGS-bench-pow = -lm
@@ -60,5 +64,19 @@ rint-ARGLIST = double
 rint-RET = double
 LDFLAGS-bench-rint = -lm
 
+# exp function slowest path
+slowexp-ITER = 3e5
+slowexp-ARGLIST = double
+slowexp-RET = double
+slowexp-INCLUDE = slowexp.c
+LDFLAGS-bench-slowexp = -lm
+
+# pow function slowest path
+slowpow-ITER = 1e5
+slowpow-ARGLIST = double:double
+slowpow-RET = double
+slowpow-INCLUDE = slowpow.c
+LDFLAGS-bench-slowpow = -lm
+
 include ../Makeconfig
 include ../Rules

benchtests/exp-inputs

@@ -1 +1 @@
-708.00096423260981737257679924368858
+42

benchtests/pow-inputs

@@ -1 +1 @@
-1.0000000000000020, 1.5
+42.0, 42.0

benchtests/slowexp-inputs

@@ -0,0 +1 @@
+708.00096423260981737257679924368858

benchtests/slowexp.c

@@ -0,0 +1,19 @@
+/* Define slowexp.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define slowexp exp

benchtests/slowpow-inputs

@@ -0,0 +1 @@
+1.0000000000000020, 1.5

benchtests/slowpow.c

@@ -0,0 +1,19 @@
+/* Define slowpow.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define slowpow pow