Backport PR #13050: Make Ipython.utils.timing work with jupyterlite

IPython/utils/timing.py

@@ -1,116 +1,123
 # encoding: utf-8
 """
 Utilities for timing code execution.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import time
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 # If possible (Unix), use the resource module instead of time.clock()
 try:
     import resource
+except ImportError:
+    resource = None
+
+# Some implementations (like jyputerlite) don't have getrusage
+if resource is not None and hasattr(resource, "getrusage"):
     def clocku():
         """clocku() -> floating point number
 
         Return the *USER* CPU time in seconds since the start of the process.
         This is done via a call to resource.getrusage, so it avoids the
         wraparound problems in time.clock()."""
 
         return resource.getrusage(resource.RUSAGE_SELF)[0]
 
     def clocks():
         """clocks() -> floating point number
 
         Return the *SYSTEM* CPU time in seconds since the start of the process.
         This is done via a call to resource.getrusage, so it avoids the
         wraparound problems in time.clock()."""
 
         return resource.getrusage(resource.RUSAGE_SELF)[1]
 
     def clock():
         """clock() -> floating point number
 
         Return the *TOTAL USER+SYSTEM* CPU time in seconds since the start of
         the process.  This is done via a call to resource.getrusage, so it
         avoids the wraparound problems in time.clock()."""
 
         u,s = resource.getrusage(resource.RUSAGE_SELF)[:2]
         return u+s
 
     def clock2():
         """clock2() -> (t_user,t_system)
 
         Similar to clock(), but return a tuple of user/system times."""
         return resource.getrusage(resource.RUSAGE_SELF)[:2]
-except ImportError:
+
+
+else:
     # There is no distinction of user/system time under windows, so we just use
     # time.perff_counter() for everything...
     clocku = clocks = clock = time.perf_counter
     def clock2():
         """Under windows, system CPU time can't be measured.
 
         This just returns perf_counter() and zero."""
         return time.perf_counter(),0.0
 
     
 def timings_out(reps,func,*args,**kw):
     """timings_out(reps,func,*args,**kw) -> (t_total,t_per_call,output)
 
     Execute a function reps times, return a tuple with the elapsed total
     CPU time in seconds, the time per call and the function's output.
 
     Under Unix, the return value is the sum of user+system time consumed by
     the process, computed via the resource module.  This prevents problems
     related to the wraparound effect which the time.clock() function has.
 
     Under Windows the return value is in wall clock seconds. See the
     documentation for the time module for more details."""
 
     reps = int(reps)
     assert reps >=1, 'reps must be >= 1'
     if reps==1:
         start = clock()
         out = func(*args,**kw)
         tot_time = clock()-start
     else:
         rng = range(reps-1) # the last time is executed separately to store output
         start = clock()
         for dummy in rng: func(*args,**kw)
         out = func(*args,**kw)  # one last time
         tot_time = clock()-start
     av_time = tot_time / reps
     return tot_time,av_time,out
 
 
 def timings(reps,func,*args,**kw):
     """timings(reps,func,*args,**kw) -> (t_total,t_per_call)
 
     Execute a function reps times, return a tuple with the elapsed total CPU
     time in seconds and the time per call. These are just the first two values
     in timings_out()."""
 
     return timings_out(reps,func,*args,**kw)[0:2]
 
 
 def timing(func,*args,**kw):
     """timing(func,*args,**kw) -> t_total
 
     Execute a function once, return the elapsed total CPU time in
     seconds. This is just the first value in timings_out()."""
 
     return timings_out(1,func,*args,**kw)[0]