Ingo Molnar <mi...@kernel.org> writes: > > Especially on modern x86 CPUs with stack engines (latest Intel and AMD > CPUs) that keeps ESP updates out of the later stages of execution > pipelines, going from RBP framepointers to direct ESP use is > beneficial to performance and compresses I$ footprint as well:
Note that Atom doesn't have this stack engine, so you'll likely see even more difference there. > So the performance advantages of not doing framepointers is not > something we can ignore IMHO: Agreed. > but obviously performance isn't > everything - so if stack unwinding is unrobust, then we need and > want frame pointers. It wasn't that bad in the old days with the approx stack traces. In fact I bet it would be possible to write an automated tool that weeds out many (most?) false positives automatically with a static compile-time callgraph. It would be good to at least make it easier building without them again. Currently it's very difficult because a lot of subsystems force select frame pointers. -Andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
