improve myrandom() in fasta.

add script to automate timing

R=rsc
DELTA=78  (68 added, 0 deleted, 10 changed)
OCL=32729
CL=32732

diff --git a/test/bench/fasta.go b/test/bench/fasta.go
index fd31400c814f91b5ac881a24156b5a40eef705c9..7919f720451d290d688903d6f451fb632b73ab36 100644 (file)
--- a/test/bench/fasta.go
+++ b/test/bench/fasta.go
@@ -66,7 +66,7 @@ type AminoAcid struct {
 var    lastrandom uint32 = 42
 
 // Random number between 0.0 and 1.0
-func myrandom() float {
+func Zmyrandom() float {
        const (
                IM = 139968;
                IA = 3877;
@@ -74,7 +74,25 @@ func myrandom() float {
        )
        lastrandom = (lastrandom * IA + IC) % IM;
        // Integer to float conversions are faster if the integer is signed.
-       return float(lastrandom) / IM;
+       return float(int32(lastrandom)) / IM;
+}
+
+// TODO: delete this when compiler does the reduction for us
+func
+myrandom() float
+{
+       const (
+               IM = 139968;
+               IA = 3877;
+               IC = 29573;
+               S = 46;
+               IM1 = ((1<<S) + IM) / IM;
+       )
+
+       n := (lastrandom * IA + IC);
+       q := uint32((uint64(n) * IM1) >> S);
+       lastrandom = n - q*IM;
+       return float(int32(lastrandom)) / IM;
 }
 
 func AccumulateProbabilities(genelist []AminoAcid) {

diff --git a/test/bench/timing.log b/test/bench/timing.log
index 71be82ca5d0a97028937667cd65f3e855727e069..9f25b573c9fa31dfc06f319165cca7e17c2d9f58 100644 (file)
--- a/test/bench/timing.log
+++ b/test/bench/timing.log
@@ -6,13 +6,28 @@ First version of fasta. Translation of fasta.c, fetched from
        http://shootout.alioth.debian.org/u32q/benchmark.php?test=fasta&lang=gpp&id=4
 
 fasta -n 25000000
-       [gcc -O2 fasta.c        5.98u 0.00s 6.01r]
-       gccgo -O2       8.82u 0.02s 8.85r
-       6g      13.50u 0.02s 13.53r
-       6g -B   12.99u 0.02s 13.02r
+       gcc -O2 fasta.c 5.98u 0.00s 6.01r
+       gccgo -O2 fasta.go      8.82u 0.02s 8.85r
+       6g fasta.go     13.50u 0.02s 13.53r
+       6g -B fata.go   12.99u 0.02s 13.02r
+
+Aug 4 2009
+[added timing.sh]
+
+# myrandom:
+#   hand-written optimization of integer division
+#   use int32->float conversion
+fasta -n 25000000
+       gcc -O2 fasta.c 5.99u 0.00s 6.00r 
+       gccgo -O2 fasta.go      8.82u 0.02s 8.85r
+       gc fasta        10.70u 0.00s 10.77r
+       gc_B fasta      10.09u 0.03s 10.12r
 
 reverse-complement < output-of-fasta-25000000
-       [gcc -O2 reverse-complement.c   2.03u 0.84s 13.04r]
-       gccgo -O2       6.47u 1.14s 15.58r
-       6g      6.55u 1.21s 15.45r
-       6g -B   6.19u 1.26s 15.64r
+       gcc -O2 reverse-complement.c    2.04u 0.94s 10.54r
+       gccgo -O2 reverse-complement.go 6.54u 0.63s 7.17r
+       gc reverse-complement   6.55u 0.70s 7.26r
+       gc_B reverse-complement 6.32u 0.70s 7.10r
+
+nbody -n 50000000
+       gcc -O2 nbody.c 21.33u 0.00s 21.34r

diff --git a/test/bench/timing.sh b/test/bench/timing.sh
new file mode 100755 (executable)
index 0000000..f80f247
--- /dev/null
+++ b/test/bench/timing.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+# Copyright 2009 The Go Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+set -e
+. $GOROOT/src/Make.$GOARCH
+
+gc() {
+       $GC $1.go; $LD $1.$O
+}
+
+gc_B() {
+       $GC -B $1.go; $LD $1.$O
+}
+
+run() {
+       echo -n '       '$1'    '
+       $1
+       shift
+       (/home/r/plan9/bin/time $* 2>&1 >/dev/null) |  sed 's/r.*/r/'
+}
+
+echo 'fasta -n 25000000'
+run 'gcc -O2 fasta.c' a.out 25000000
+#run 'gccgo -O2 fasta.go' a.out -n 25000000    #commented out until WriteString is in bufio
+run 'gc fasta' $O.out -n 25000000
+run 'gc_B fasta' $O.out -n 25000000
+
+echo
+6.out -n 25000000 > x
+echo 'reverse-complement < output-of-fasta-25000000'
+run 'gcc -O2 reverse-complement.c' a.out 25000000 < x
+run 'gccgo -O2 reverse-complement.go' a.out -n 25000000 < x
+run 'gc reverse-complement' $O.out -n 25000000 < x
+run 'gc_B reverse-complement' $O.out -n 25000000 < x
+rm x
+