pip on cygwin (both x86 and x64) painfully slow

[PikalaxALT]

System: Windows 8.1 x64, Cygwin x86-64 or Cygwin x86, Python 2.7.9

Command: pip list

What I expect:
Output within 5 seconds, as experienced when pip is called from Windows Command Prompt or any SSH session

What I observe:
pip hangs for as long as 30 minutes with no output to the console. It can still be interrupted.

Additional observations:

$ pip list -vvv
### 1 minute later
Starting new HTTPS connection (1): pypi.python.org
"GET /pypi/pip/json HTTP/1.1" 200 38302

I give up on waiting after around 30 minutes of inactivity.

[PikalaxALT]

Update: Slowness of pip not observed when cygwin is installed on the system disk. Is observed when installed on a portable flash drive or external hard drive.

[thorstenkampe]

I think the main issue is not slowness but that pip hangs indefinitely (also during installs, that's why I use easy_install).
I think this is a problem with locking on a flash drive when the file system is Microsoft's new file system exFAT:

Traceback (most recent call last):
  File "/usr/bin/pip", line 9, in <module>
    load_entry_point('pip==7.1.2', 'console_scripts', 'pip')()
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/__init__.py", line 217, in main
    return command.main(cmd_args)
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/basecommand.py", line 248, in main
    pip_version_check(session)
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/utils/outdated.py", line 138, in pip_version_check
    state.save(pypi_version, current_time)
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/utils/outdated.py", line 71, in save
    with lockfile.LockFile(self.statefile_path):
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/_vendor/lockfile/__init__.py", line 238, in __enter__
    self.acquire()
  File "/usr/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/_vendor/lockfile/linklockfile.py", line 49, in acquire
    time.sleep(timeout is not None and timeout/10 or 0.1)

[phdye]

I experienced the same issue and found it to be a permissions problem with $HOME/.cache. Once I resolved that, pip has work perfectly.

In my case, ~/.cache was owned by a another user. That might be unusual but permissions appears to be a common cause in this situation.

[dstufft]

Closing as a duplicate of #3532.