Author: Laurence Tratt <[email protected]>
Branch: recursion_and_inlining
Changeset: r74470:b60064f55316
Date: 2014-11-11 15:54 +0000
http://bitbucket.org/pypy/pypy/changeset/b60064f55316/
Log: Stop tracing when inlining is detected.
Currently, if a function called part way through a trace turns out
to be recursively, it is endlessly inlined, often leading to a
tracing abort. This is tremendously inefficient, and many seemingly
innocent recursive functions have extremely bad performance
characteristics.
This patch is the first step in trying to address this. Notice that
this breaks a few tests, in the sense that it changes what is
traced. It should have no visible effect on end behaviour.
diff --git a/rpython/jit/metainterp/pyjitpl.py
b/rpython/jit/metainterp/pyjitpl.py
--- a/rpython/jit/metainterp/pyjitpl.py
+++ b/rpython/jit/metainterp/pyjitpl.py
@@ -951,9 +951,31 @@
assembler_call = False
if warmrunnerstate.inlining:
if warmrunnerstate.can_inline_callable(greenboxes):
+ # We've found a potentially inlinable function; now we need to
+ # see if it's already on the stack. In other words: are we
about
+ # to enter recursion? If so, we don't want to inline the
+ # recursion, which would be equivalent to unrolling a while
+ # loop.
portal_code = targetjitdriver_sd.mainjitcode
- return self.metainterp.perform_call(portal_code, allboxes,
- greenkey=greenboxes)
+ inline = True
+ if self.metainterp.is_main_jitcode(portal_code):
+ for gk, _ in self.metainterp.portal_trace_positions:
+ if gk is None:
+ continue
+ assert len(gk) == len(greenboxes)
+ i = 0
+ for i in range(len(gk)):
+ if not gk[i].same_constant(greenboxes[i]):
+ break
+ else:
+ # The greenkey of a trace position on the stack
+ # matches what we have, which means we're
definitely
+ # about to recurse.
+ inline = False
+ break
+ if inline:
+ return self.metainterp.perform_call(portal_code, allboxes,
+ greenkey=greenboxes)
assembler_call = True
# verify that we have all green args, needed to make sure
# that assembler that we call is still correct
_______________________________________________
pypy-commit mailing list
[email protected]
https://mail.python.org/mailman/listinfo/pypy-commit
