perf: introduce a `perf.run-limits` options

This options make it possible to configure the number of run that the extensions
will perform. This is useful for automated benchmark or for performance
measurement that need better accuracy.

contrib/perf.py

@@ -15,6 +15,16 b' Configurations'
 ``presleep``
   number of second to wait before any group of run (default: 1)
 
+``run-limits``
+  Control the number of run each benchmark will perform. The option value
+  should be a list of `<time>-<numberofrun>` pairs. After each run the
+  condition are considered in order with the following logic:
+
+      If benchmark have been running for <time> seconds, and we have performed
+      <numberofrun> iterations, stop the benchmark,
+
+  The default value is: `3.0-100, 10.0-3`
+
 ``stub``
     When set, benchmark will only be run once, useful for testing (default: off)
 '''
@@ -225,6 +235,9 b' try:'
     configitem(b'perf', b'all-timing',
         default=mercurial.configitems.dynamicdefault,
     )
+    configitem(b'perf', b'run-limits',
+        default=mercurial.configitems.dynamicdefault,
+    )
 except (ImportError, AttributeError):
     pass
 
@@ -297,7 +310,34 b' def gettimer(ui, opts=None):'
 
     # experimental config: perf.all-timing
     displayall = ui.configbool(b"perf", b"all-timing", False)
-    return functools.partial(_timer, fm, displayall=displayall), fm
+
+    # experimental config: perf.run-limits
+    limitspec = ui.configlist(b"perf", b"run-limits", [])
+    limits = []
+    for item in limitspec:
+        parts = item.split('-', 1)
+        if len(parts) < 2:
+            ui.warn(('malformatted run limit entry, missing "-": %s\n'
+                     % item))
+            continue
+        try:
+            time_limit = float(parts[0])
+        except ValueError as e:
+            ui.warn(('malformatted run limit entry, %s: %s\n'
+                     % (e, item)))
+            continue
+        try:
+            run_limit = int(parts[1])
+        except ValueError as e:
+            ui.warn(('malformatted run limit entry, %s: %s\n'
+                     % (e, item)))
+            continue
+        limits.append((time_limit, run_limit))
+    if not limits:
+        limits = DEFAULTLIMITS
+
+    t = functools.partial(_timer, fm, displayall=displayall, limits=limits)
+    return t, fm
 
 def stub_timer(fm, func, setup=None, title=None):
     if setup is not None:

tests/test-contrib-perf.t

@@ -55,6 +55,16 b' perfstatus'
   "presleep"
     number of second to wait before any group of run (default: 1)
   
+  "run-limits"
+    Control the number of run each benchmark will perform. The option value
+    should be a list of '<time>-<numberofrun>' pairs. After each run the
+    condition are considered in order with the following logic:
+  
+        If benchmark have been running for <time> seconds, and we have performed
+        <numberofrun> iterations, stop the benchmark,
+  
+    The default value is: '3.0-100, 10.0-3'
+  
   "stub"
       When set, benchmark will only be run once, useful for testing (default:
       off)
@@ -231,6 +241,31 b' perfstatus'
   $ hg perfparents
   $ hg perfdiscovery -q .
 
+Test run control
+----------------
+
+Simple single entry
+
+  $ hg perfparents --config perf.stub=no --config perf.run-limits='0.000000001-15'
+  ! wall * comb * user * sys * (best of 15) (glob)
+
+Multiple entries
+
+  $ hg perfparents --config perf.stub=no --config perf.run-limits='500000-1, 0.000000001-5'
+  ! wall * comb * user * sys * (best of 5) (glob)
+
+error case are ignored
+
+  $ hg perfparents --config perf.stub=no --config perf.run-limits='500, 0.000000001-5'
+  malformatted run limit entry, missing "-": 500
+  ! wall * comb * user * sys * (best of 5) (glob)
+  $ hg perfparents --config perf.stub=no --config perf.run-limits='aaa-12, 0.000000001-5'
+  malformatted run limit entry, could not convert string to float: aaa: aaa-12
+  ! wall * comb * user * sys * (best of 5) (glob)
+  $ hg perfparents --config perf.stub=no --config perf.run-limits='12-aaaaaa, 0.000000001-5'
+  malformatted run limit entry, invalid literal for int() with base 10: 'aaaaaa': 12-aaaaaa
+  ! wall * comb * user * sys * (best of 5) (glob)
+
 test actual output
 ------------------