From f84587776771bf8c5e665a118e604494e98b6ea1 Mon Sep 17 00:00:00 2001
From: Steve Holden <steve@holdenweb.com>
Date: Fri, 26 May 2006 17:41:32 +0000
Subject: [PATCH] Use minimum calibration time rather than avergae to avoid the
 illusion of negative run times. Halt with an error if run times go below 10
 ms, indicating that results will be unreliable.

---
 Tools/pybench/pybench.py | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/Tools/pybench/pybench.py b/Tools/pybench/pybench.py
index c4fd8ff2a8..8df0025f2e 100755
--- a/Tools/pybench/pybench.py
+++ b/Tools/pybench/pybench.py
@@ -126,7 +126,7 @@ class Test:
         self.operations = self.operations
         self.rounds = self.rounds
 
-    def run(self):
+    def run(self, cruns):
 
         """ Run the test in two phases: first calibrate, then
             do the actual test. Be careful to keep the calibration
@@ -136,20 +136,23 @@ class Test:
         test = self.test
         calibrate = self.calibrate
         clock = time.clock
-        cruns = self.cruns
         # first calibrate
-        offset = 0.0
+        t = clock()
+        calibrate()
+        offset = clock() - t
         if cruns:
-            for i in range(cruns):
+            for i in range(cruns-1):
                 t = clock()
                 calibrate()
                 t = clock() - t
-                offset = offset + t
-            offset = offset / cruns
+                if t < offset:
+                    offset = t
         # now the real thing
         t = clock()
         test()
         t = clock() - t
+        if t < 0.01:
+            sys.exit("Lower warp required: test times < 10 ms are unreliable")
         self.last_timing = (t-offset,t,offset)
         self.times.append(t-offset)
 
@@ -253,7 +256,7 @@ class Benchmark:
             print len(l), "tests found"
         print
 
-    def run(self, verbose):
+    def run(self, verbose, cruns):
 
         tests = self.tests.items()
         tests.sort()
@@ -266,10 +269,10 @@ class Benchmark:
             if verbose:
                 print ' Round %-25i  real   abs    overhead' % (i+1)
             for j in range(len(tests)):
-                name,t = tests[j]
+                name, t = tests[j]
                 if verbose:
                     print '%30s:' % name,
-                t.run()
+                t.run(cruns)
                 if verbose:
                     print '  %.3fr %.3fa %.3fo' % t.last_timing
             if verbose:
@@ -379,7 +382,7 @@ class PyBenchCmdline(Application):
                SwitchOption('--no-syscheck',
                     '"disable" sys check interval (set to sys.maxint)', 0),
                ArgumentOption('-t', 'tests containing substring', ''),
-               ArgumentOption('-C', 'number of calibration runs (default 0)', '')
+               ArgumentOption('-C', 'number of calibration runs (default 20)', 20)
                ]
 
     about = """\
@@ -423,7 +426,9 @@ python pybench.py -s p15 -c p14
         limitnames = self.values['-t']
         verbose = self.verbose
         nosyscheck = self.values['--no-syscheck']
-
+        cruns = self.values['-C']
+        print "CRUNS:", cruns
+        
         print 'PYBENCH',__version__
 
         # Switch off GC
@@ -488,7 +493,7 @@ python pybench.py -s p15 -c p14
         bench.rounds = rounds
         bench.load_tests(Setup, warp, limitnames, verbose)
         try:
-            bench.run(verbose)
+            bench.run(verbose, cruns)
         except KeyboardInterrupt:
             print
             print '*** KeyboardInterrupt -- Aborting'
-- 
2.40.0