Movatterモバイル変換
[0]ホーム
[Python-Dev] [numpy wishlist] Interpreter support for temporary elision in third-party classes
Sturla Moldensturla.molden at gmail.com
Fri Jun 6 04:18:05 CEST 2014
On 05/06/14 22:51, Nathaniel Smith wrote:> This gets evaluated as:>> tmp1 = a + b> tmp2 = tmp1 + c> result = tmp2 / c>> All these temporaries are very expensive. Suppose that a, b, c are> arrays with N bytes each, and N is large. For simple arithmetic like> this, then costs are dominated by memory access. Allocating an N byte> array requires the kernel to clear the memory, which incurs N bytes of> memory traffic.It seems to be the case that a large portion of the run-time in Python code using NumPy can be spent in the kernel zeroing pages (which the kernel does for security reasons).I think this can also be seen as a 'malloc problem'. It comes about because each new NumPy array starts with a fresh buffer allocated by malloc. Perhaps buffers can be reused?Sturla
More information about the Python-Devmailing list
[8]ページ先頭