On 27/06/2025 17:36, Kees Cook wrote:
On Wed, Jun 25, 2025 at 05:12:20PM +0100, Colin Ian King wrote:Analysis with gcov while running the stress-ng urandom stressor shows that there are a couple of fortify panic paths that are highly unlikely to be executed for well-behaving code. Adding appropriate branch hints improves the stress-ng urandom stressor my a small but statistically measureable amount. Ran 100 x 1 minute tests and measured the stressor bogo-op rates on a Debian based Intel(R) Core(TM) Ultra 9 285K with a 6.15 kernel with turbo disabled to reduce jitter. Results based on a Geometic Mean of 100 tests: Without patch: 50512.95 bogo-ops/sec With patch: 50819.58 bogo-ops/sec %Std.Deviation of ~0.18%, so low jitter in results, improvement of ~0.6% Signed-off-by: Colin Ian King <colin.i.king@xxxxxxxxx>Nice find! It seems some ftrace configs are unhappy with this change, though?
I'll resend once I get some time to figure out the issues with the ftrace configs
Colin
-Kees
Attachment:
OpenPGP_0x68C287DFC6A80226.asc
Description: OpenPGP public key
Attachment:
OpenPGP_signature.asc
Description: OpenPGP digital signature
