impr: Optimized the format_number function

[DebanKsahu]

Description

• So I was going through the code and encountered the function format_number where there is a branch which try to convert the number into 2^x format if possible. Previously the code iterate over the number till it become <2 and during that it count power but it can be easily done by simple bit manipulation.
• A number can only be converted into 2^x if there is only one active bit means number & (number-1) will be 0 and power would be position of that active bit which is length-1.

[vstinner]

Can you please apply this change on your PR?

diff --git a/pyperf/tests/test_utils.py b/pyperf/tests/test_utils.py
index edf8549..52d08ad 100644
--- a/pyperf/tests/test_utils.py
+++ b/pyperf/tests/test_utils.py
@@ -130,15 +130,16 @@ class TestUtils(unittest.TestCase):
         self.assertEqual(format_number(33 * 10 ** 4, 'unit'),
                          '330000 units')
 
-        # powers of 10
+        # powers of 2
         self.assertEqual(format_number(2 ** 10, 'unit'),
                          '1024 units')
         self.assertEqual(format_number(2 ** 15, 'unit'),
                          '2^15 units')
         self.assertEqual(format_number(2 ** 15),
                          '2^15')
-        self.assertEqual(format_number(2 ** 10 + 1, 'unit'),
-                         '1025 units')
+        # not powers of 2
+        self.assertEqual(format_number(2 ** 15 - 1), '32767')
+        self.assertEqual(format_number(2 ** 15 + 1), '32769')
 
     def test_format_filesize(self):
         self.assertEqual(format_filesize(0),

Currently, the tests don't cover well numbers which are close to power of 2 but are not power of 2.

[DebanKsahu]

Sure