Author: Armin Rigo <ar...@tunes.org>
Branch:
Changeset: r80914:9bbd8daa83aa
Date: 2015-11-24 22:00 +0100
http://bitbucket.org/pypy/pypy/changeset/9bbd8daa83aa/
Log: A fast-path for the JIT: in the common case, ffi.init_once() is
known during tracing to have been done already, and turns into no
code at all
diff --git a/pypy/module/_cffi_backend/ffi_obj.py
b/pypy/module/_cffi_backend/ffi_obj.py
--- a/pypy/module/_cffi_backend/ffi_obj.py
+++ b/pypy/module/_cffi_backend/ffi_obj.py
@@ -50,6 +50,7 @@
w_gc_wref_remove = None
w_init_once_cache = None
+ jit_init_once_cache = None
@jit.dont_look_inside
def __init__(self, space, src_ctx):
@@ -589,11 +590,30 @@
def descr_init_once(self, w_func, w_tag):
"""XXX document me"""
#
- # atomically get or create a new dict (no GIL release)
+ # first, a fast-path for the JIT which only works if the very
+ # same w_tag object is passed; then it turns into no code at all
+ try:
+ return self._init_once_elidable(w_tag)
+ except KeyError:
+ return self._init_once_slowpath(w_func, w_tag)
+
+ @jit.elidable
+ def _init_once_elidable(self, w_tag):
+ jit_cache = self.jit_init_once_cache
+ if jit_cache is not None:
+ return jit_cache[w_tag]
+ else:
+ raise KeyError
+
+ @jit.dont_look_inside
+ def _init_once_slowpath(self, w_func, w_tag):
space = self.space
w_cache = self.w_init_once_cache
if w_cache is None:
- w_cache = self.w_init_once_cache = space.newdict()
+ w_cache = self.space.newdict()
+ jit_cache = {}
+ self.w_init_once_cache = w_cache
+ self.jit_init_once_cache = jit_cache
#
# get the lock or result from cache[tag]
w_res = space.finditem(w_cache, w_tag)
@@ -606,6 +626,7 @@
w_res = space.finditem(w_cache, w_tag)
if w_res is None or isinstance(w_res, W_InitOnceLock):
w_res = space.call_function(w_func)
+ self.jit_init_once_cache[w_tag] = w_res
space.setitem(w_cache, w_tag, w_res)
else:
# the real result was put in the dict while we were
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