Yet Another Python Profiler, but this time thread&coroutine&greenlet aware.
- Fast: Yappi is fast. It is completely written in C and lots of love&care went into making it fast.
- Unique: Yappi supports multithreaded, asyncio and gevent profiling. Tagging/filtering multiple profiler results has interesting use cases.
- Intuitive: Profiler can be started/stopped and results can be obtained from any time and any thread.
- Standards Complaint: Profiler results can be saved in callgrind or pstat formats.
- Rich in Feature set: Profiler results can show either Wall Time or actual CPU Time and can be aggregated from different sessions. Various flags are defined for filtering and sorting profiler results.
- Robust: Yappi had seen years of production usage.
CPython standard distribution comes with three deterministic profilers. cProfile, Profile and hotshot. cProfile is implemented as a C module based on lsprof, Profile is in pure Python and hotshot can be seen as a small subset of a cProfile. The major issue is that all of these profilers lack support for multi-threaded programs and CPU time.
If you want to profile a multi-threaded application, you must give an entry point to these profilers and then maybe merge the outputs. None of these profilers are designed to work on long-running multi-threaded applications. It is also not possible to profile an application that start/stop/retrieve traces on the fly with these profilers.
Now fast forwarding to 2019: With the latest improvements on asyncio library and asynchronous frameworks, most of the current profilers lacks the ability to show correct wall/cpu time or even call count information per-coroutine. Thus we need a different kind of approach to profile asynchronous code. Yappi, with v1.2 introduces the concept of coroutine profiling. With coroutine-profiling, you should be able to profile correct wall/cpu time and call count of your coroutine. (including the time spent in context switches, too). You can see details here.
Can be installed via PyPI
$ pip install yappi
OR from the source directly.
$ pip install git+https://github.com/sumerc/yappi#egg=yappi
import yappi
def a():
for _ in range(10000000): # do something CPU heavy
pass
yappi.set_clock_type("cpu") # Use set_clock_type("wall") for wall time
yappi.start()
a()
yappi.get_func_stats().print_all()
yappi.get_thread_stats().print_all()
'''
Clock type: CPU
Ordered by: totaltime, desc
name ncall tsub ttot tavg
doc.py:5 a 1 0.117907 0.117907 0.117907
name id tid ttot scnt
_MainThread 0 139867147315008 0.118297 1
'''You can profile a multithreaded application via Yappi and can easily retrieve
per-thread profile information by filtering on ctx_id with get_func_stats API.
import yappi
import time
import threading
_NTHREAD = 3
def _work(n):
time.sleep(n * 0.1)
yappi.start()
threads = []
# generate _NTHREAD threads
for i in range(_NTHREAD):
t = threading.Thread(target=_work, args=(i + 1, ))
t.start()
threads.append(t)
# wait all threads to finish
for t in threads:
t.join()
yappi.stop()
# retrieve thread stats by their thread id (given by yappi)
threads = yappi.get_thread_stats()
for thread in threads:
print(
"Function stats for (%s) (%d)" % (thread.name, thread.id)
) # it is the Thread.__class__.__name__
yappi.get_func_stats(ctx_id=thread.id).print_all()
'''
Function stats for (Thread) (3)
name ncall tsub ttot tavg
..hon3.7/threading.py:859 Thread.run 1 0.000017 0.000062 0.000062
doc3.py:8 _work 1 0.000012 0.000045 0.000045
Function stats for (Thread) (2)
name ncall tsub ttot tavg
..hon3.7/threading.py:859 Thread.run 1 0.000017 0.000065 0.000065
doc3.py:8 _work 1 0.000010 0.000048 0.000048
Function stats for (Thread) (1)
name ncall tsub ttot tavg
..hon3.7/threading.py:859 Thread.run 1 0.000010 0.000043 0.000043
doc3.py:8 _work 1 0.000006 0.000033 0.000033
'''You can use filter_callback on get_func_stats API to filter on functions, modules
or whatever available in YFuncStat object.
import package_a
import yappi
import sys
def a():
pass
def b():
pass
yappi.start()
a()
b()
package_a.a()
yappi.stop()
# filter by module object
current_module = sys.modules[__name__]
stats = yappi.get_func_stats(
filter_callback=lambda x: yappi.module_matches(x, [current_module])
) # x is a yappi.YFuncStat object
stats.sort("name", "desc").print_all()
'''
Clock type: CPU
Ordered by: name, desc
name ncall tsub ttot tavg
doc2.py:10 b 1 0.000001 0.000001 0.000001
doc2.py:6 a 1 0.000001 0.000001 0.000001
'''
# filter by function object
stats = yappi.get_func_stats(
filter_callback=lambda x: yappi.func_matches(x, [a, b])
).print_all()
'''
name ncall tsub ttot tavg
doc2.py:6 a 1 0.000001 0.000001 0.000001
doc2.py:10 b 1 0.000001 0.000001 0.000001
'''
# filter by module name
stats = yappi.get_func_stats(filter_callback=lambda x: 'package_a' in x.module
).print_all()
'''
name ncall tsub ttot tavg
package_a/__init__.py:1 a 1 0.000001 0.000001 0.000001
'''
# filter by function name
stats = yappi.get_func_stats(filter_callback=lambda x: 'a' in x.name
).print_all()
'''
name ncall tsub ttot tavg
doc2.py:6 a 1 0.000001 0.000001 0.000001
package_a/__init__.py:1 a 1 0.000001 0.000001 0.000001
'''You can see that coroutine wall-time's are correctly profiled.
import asyncio
import yappi
async def foo():
await asyncio.sleep(1.0)
await baz()
await asyncio.sleep(0.5)
async def bar():
await asyncio.sleep(2.0)
async def baz():
await asyncio.sleep(1.0)
yappi.set_clock_type("WALL")
with yappi.run():
asyncio.run(foo())
asyncio.run(bar())
yappi.get_func_stats().print_all()
'''
Clock type: WALL
Ordered by: totaltime, desc
name ncall tsub ttot tavg
doc4.py:5 foo 1 0.000030 2.503808 2.503808
doc4.py:11 bar 1 0.000012 2.002492 2.002492
doc4.py:15 baz 1 0.000013 1.001397 1.001397
'''You can use yappi to profile greenlet applications now!
import yappi
from greenlet import greenlet
import time
class GreenletA(greenlet):
def run(self):
time.sleep(1)
yappi.set_context_backend("greenlet")
yappi.set_clock_type("wall")
yappi.start(builtins=True)
a = GreenletA()
a.switch()
yappi.stop()
yappi.get_func_stats().print_all()
'''
name ncall tsub ttot tavg
tests/test_random.py:6 GreenletA.run 1 0.000007 1.000494 1.000494
time.sleep 1 1.000487 1.000487 1.000487
'''-
Coroutine Profiling (new in 1.2)
-
Greenlet Profiling (new in 1.3)
Note: Yes. I know I should be moving docs to readthedocs.io. Stay tuned!
Special thanks to A.Jesse Jiryu Davis:
Yappi is the default profiler in PyCharm. If you have Yappi installed, PyCharm will use it. See the official documentation for more details.