2011/10/6 mark florisson <[email protected]>: > On 6 October 2011 07:46, Stefan Behnel <[email protected]> wrote: >> mark florisson, 05.10.2011 15:53: >>> >>> On 5 October 2011 08:16, Stefan Behnel wrote: >>>> >>>> mark florisson, 04.10.2011 23:19: >>>>> >>>>> Another issue is that Cython compile time is increasing with the >>>>> addition of control flow and cython utilities. If you use fused types >>>>> you're also going to combinatorially add more compile time. >>>> >>>> I don't see that locally - a compiled Cython is hugely fast for me. In >>>> comparison, the C compiler literally takes ages to compile the result. An >>>> external shared library may or may not help with both - in particular, it >>>> is >>>> not clear to me what makes the C compiler slow. If the compile time is >>>> dominated by the number of inlined functions (which is not unlikely), a >>>> shared library + header file will not make a difference. >>> >>> Have you tried with the memoryviews merged? >> >> No. I didn't expect the difference to be quite that large. >> >> >>> e.g. if I have this code: >>> >>> from libc.stdlib cimport malloc >>> cdef int[:] slice =<int[:10]> <int *> malloc(sizeof(int) * 10) >>> >>> [0] [14:45] ~ ➤ time cython test.pyx >>> cython test.pyx 2.61s user 0.08s system 99% cpu 2.695 total >>> [0] [14:45] ~ ➤ time zsh compile >>> zsh compile 1.88s user 0.06s system 99% cpu 1.946 total >>> >>> where 'compile' is the script that invoked the same gcc command >>> distutils uses. As you can see it took more than 2.5 seconds to >>> compile this code (simply because the memoryview utilities get >>> included). >> >> Ok, that hints at serious performance problems. Could you profile it to see >> where the issues are? Is it more that the code is loaded from an external >> file? Or the fact that more utility code is parsed than necessary? > > I haven't profiled it yet (I'll do that), but I'm fairly sure it's the > parsing of Cython utility files (not the loading). Maybe Tempita also > adds to the overhead, I'll find out. >
Compiling this regex gives 5ms instead of 10ms on my machine https://github.com/cython/cython/blob/master/Cython/Compiler/Code.py#L85 And on your example gives 3% speedup >> It's certainly not obvious why the inclusion of static code, even from an >> external file, should make any difference. >> >> That being said, it's not we were lacking the infrastructure for making >> Python code run faster ... >> > > Heh, indeed. In this case I think caching will solve all our problems. > >>>>> I'm sure >>>>> this came up earlier, but I really think we should have a libcython >>>>> and a cython.h. libcython (a shared library) should contain any common >>>>> Cython-specific code not meant to be inlined, and cython.h any types, >>>>> macros and inline functions etc. >>>> >>>> This has a couple of implications though. In order to support this on the >>>> user side, we have to build one shared library per installed package in >>>> order to avoid any Cython versioning issues. Just installing a versioned >>>> "libcython_x.y.z.so" globally isn't enough, especially during >>>> development, >>>> but also at deployment time. Different packages may use different CFLAGS >>>> or >>>> Cython options, which may have an impact on the result. Encoding all >>>> possible factors in the file name will be cumbersome and may mean that we >>>> still end up with a number of installed Cython libraries that correlates >>>> with the number of installed Cython based packages. >>> >>> Hm, I think the CFLAGS are important so long as they are compatible >>> with Python. When the user compiles a Cython extension module with >>> extra CFLAGS, this doesn't affect libpython. Similarly, the Cython >>> utilities are really not the user's responsibility, so libcython >>> doesn't need to be compiled with the same flags as the extension >>> module. If still wanted, the user could either recompile python with >>> different CFLAGS (which means libcython will get those as well), or >>> not use libcython at all. CFLAGS should really only pertain to user >>> code, not to the Cython library, which the user shouldn't be concerned >>> about. >> >> Well, it's either the user or the OS distribution that installs (and >> potentially builds) the libraries. That already makes it two responsible >> entities for many systems that have to agree on what gets installed in what >> way. I'm just saying, don't underestimate the details in world wide >> deployments. >> -- vitja. _______________________________________________ cython-devel mailing list [email protected] http://mail.python.org/mailman/listinfo/cython-devel
