Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC

Commits:

• 7b27f25a
  by Simon Jakobi at 2026-08-14T06:26:54-04:00

  testsuite: Drop peak_megabytes_allocated from LinkableUsage tests
  
  LinkableUsage01/02 collected all metrics with a 2% tolerance. For
  peak_megabytes_allocated, whose granularity is 1 MB, that window is
  under 0.7 MB at this test's ~34 MB peak, so any 1 MB step failed the
  test (#27613, #27489). Drop that metric: max_bytes_used guards the
  Linkable-retention property with byte granularity, at a tolerance
  that still comfortably exceeds the noise observed in CI.
  
  Assisted-by: Claude Fable 5
  

• e5de423b
  by Simon Jakobi at 2026-08-14T06:26:54-04:00

  testsuite: Don't truncate fractional baselines when computing bounds
  
  RelativeMetricAcceptanceWindow.get_bounds truncated the baseline with
  int() before applying the tolerance. Baselines can be fractional (they
  are averaged over several measurements), so this skewed the acceptance
  window downwards: in #27613, a baseline of 33.67 at 2% tolerance
  yielded bounds (32, 34) instead of (32, 35), rejecting a measurement
  that was within tolerance.
  
  Assisted-by: Claude Fable 5
  

2 changed files:

• testsuite/driver/perf_notes.py
• testsuite/tests/bytecode/TLinkable/all.T

Changes:

         self.__tol = tol

     def get_bounds(self, baseline: float) -> Tuple[float, float]:

-        lowerBound = trunc(           int(baseline) * ((100 - float(self.__tol))/100))

-        upperBound = trunc(0.5 + ceil(int(baseline) * ((100 + float(self.__tol))/100)))

+        lowerBound = trunc(           baseline * ((100 - float(self.__tol))/100))

+        upperBound = trunc(0.5 + ceil(baseline * ((100 + float(self.__tol))/100)))

         return (lowerBound, upperBound)

 # after they have been loaded into the `LoaderState`.

 # However, this property is currently not validated automatically.

 test('LinkableUsage01'

-    , [ collect_compiler_stats('all', 2)

+    , [ collect_compiler_stats('bytes allocated', 2)

+      , collect_compiler_stats('max_bytes_used', 5)

       , extra_files(['genLinkables.sh', 'BCOTemplate.hs'])

       , pre_cmd('$MAKE -s --no-print-directory LinkableUsage01_Prep')

       , req_bco

 # Performance test for bytecode `Linkable`s.

 test('LinkableUsage02'

-    , [ collect_compiler_stats('all', 2)

+    , [ collect_compiler_stats('bytes allocated', 2)

+      , collect_compiler_stats('max_bytes_used', 5)

       , extra_files(['genLinkables.sh', 'BCOTemplate.hs'])

       , pre_cmd('$MAKE -s --no-print-directory LinkableUsage02_Prep')

       , req_bco