view mercurial/utils/memorytop.py @ 49803:55d45d0de4e7

typing: add type hints to pycompat.bytestr

The problem with leaving pytype to its own devices here was that for functions
that returned a bytestr, pytype inferred `Union[bytes, int]`.  It now accepts
that it can be treated as plain bytes.

I wasn't able to figure out the arg type for `__getitem__`- `SupportsIndex`
(which PyCharm indicated is how the superclass function is typed) got flagged:

    File "/mnt/c/Users/Matt/hg/mercurial/pycompat.py", line 236, in __getitem__:
        unsupported operand type(s) for item retrieval: bytestr and SupportsIndex [unsupported-operands]
      Function __getitem__ on bytestr expects int

But some caller got flagged when I marked it as `int`.

There's some minor spillover problems elsewhere- pytype doesn't seem to
recognize that `bytes.startswith()` can optionally take a 3rd and 4th arg, so
those few places have the warning disabled.  It also flags where the tar API is
being abused, but that would be a tricky refactor (and would require typing
extensions until py3.7 is dropped), so disable those too.

# memorytop requires Python 3.4
#
# Usage: set PYTHONTRACEMALLOC=n in the environment of the hg invocation,
# where n>= is the number of frames to show in the backtrace. Put calls to
# memorytop in strategic places to show the current memory use by allocation
# site.

import gc
import tracemalloc


def memorytop(limit=10):
    gc.collect()
    snapshot = tracemalloc.take_snapshot()

    snapshot = snapshot.filter_traces(
        (
            tracemalloc.Filter(False, "<frozen importlib._bootstrap>"),
            tracemalloc.Filter(False, "<frozen importlib._bootstrap_external>"),
            tracemalloc.Filter(False, "<unknown>"),
        )
    )
    stats = snapshot.statistics('traceback')

    total = sum(stat.size for stat in stats)
    print("\nTotal allocated size: %.1f KiB\n" % (total / 1024))
    print("Lines with the biggest net allocations")
    for index, stat in enumerate(stats[:limit], 1):
        print(
            "#%d: %d objects using %.1f KiB"
            % (index, stat.count, stat.size / 1024)
        )
        for line in stat.traceback.format(most_recent_first=True):
            print('    ', line)

    other = stats[limit:]
    if other:
        size = sum(stat.size for stat in other)
        count = sum(stat.count for stat in other)
        print(
            "%s other: %d objects using %.1f KiB"
            % (len(other), count, size / 1024)
        )
    print()