Add tools/nanobench_flags.py.

This should look suspiciously similar to tools/dm_flags.py.  In fact, I
tweaked tools/dm_flags.py a bit to make it even more suspiciously similar.
I'll leave actually deduping this to future me.

I noticed we have an opportunity to make our Valgrind run of nanobench faster,
by not only making it not auto-calibrate (--loops 1) but also take only one
measurement (--samples 1).  Should be 5-10x faster than the default.

BUG=skia:

Review URL: https://codereview.chromium.org/957503002

1 files changed, 91 insertions, 0 deletions

diff --git a/tools/nanobench_flags.py b/tools/nanobench_flags.py
new file mode 100755
index 0000000000..18668c9dc2
--- /dev/null
+++ b/tools/nanobench_flags.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+
+usage = '''
+Write extra flags to outfile for nanobench based on the bot name:
+  $ python nanobench_flags.py outfile Perf-Android-GalaxyS3-Mali400-Arm7-Release
+Or run self-tests:
+  $ python nanobench_flags.py test
+'''
+
+import inspect
+import json
+import os
+import sys
+
+
+def lineno():
+  caller = inspect.stack()[1]  # Up one level to our caller.
+  return inspect.getframeinfo(caller[0]).lineno
+
+
+cov_start = lineno()+1   # We care about coverage starting just past this def.
+def get_args(bot):
+  args = []
+
+  args.extend(['--scales', '1.0', '1.1'])
+
+  if 'Valgrind' in bot:
+    # Don't care about Valgrind performance.
+    args.extend(['--loops',   '1'])
+    args.extend(['--samples', '1'])
+
+  match = []
+  if 'Android' in bot:
+    # Segfaults when run as GPU bench. Very large texture?
+    match.append('~blurroundrect')
+    match.append('~patch_grid')  # skia:2847
+    match.append('~desk_carsvg')
+  if 'HD2000' in bot:
+    match.extend(['~gradient', '~etc1bitmap'])  # skia:2895
+  if 'Nexus7' in bot:
+    match = ['skp']  # skia:2774
+  if match:
+    args.append('--match')
+    args.extend(match)
+
+  if ('GalaxyS3' in bot or
+      'GalaxyS4' in bot):
+    args.append('--nocpu')
+  return args
+cov_end = lineno()   # Don't care about code coverage past here.
+
+
+def self_test():
+  import coverage  # This way the bots don't need coverage.py to be installed.
+  args = {}
+  cases = [
+    'Perf-Android-GalaxyS3-Mali400-Arm7-Release',
+    'Perf-Android-Nexus7-Tegra3-Arm7-Release',
+    'Test-Ubuntu12-ShuttleA-GTX550Ti-x86_64-Release-Valgrind',
+    'Test-Win7-ShuttleA-HD2000-x86-Debug-ANGLE',
+  ]
+
+  cov = coverage.coverage()
+  cov.start()
+  for case in cases:
+    args[case] = get_args(case)
+  cov.stop()
+
+  this_file = os.path.basename(__file__)
+  _, _, not_run, _ = cov.analysis(this_file)
+  filtered = [line for line in not_run if line > cov_start and line < cov_end]
+  if filtered:
+    print 'Lines not covered by test cases: ', filtered
+    sys.exit(1)
+
+  golden = this_file.replace('.py', '.json')
+  with open(os.path.join(os.path.dirname(__file__), golden), 'w') as f:
+    json.dump(args, f, indent=2, sort_keys=True)
+
+
+if __name__ == '__main__':
+  if len(sys.argv) == 2 and sys.argv[1] == 'test':
+    self_test()
+    sys.exit(0)
+
+  if len(sys.argv) != 3:
+    print usage
+    sys.exit(1)
+
+  with open(sys.argv[1], 'w') as out:
+    json.dump(get_args(sys.argv[2]), out)