Re: [GIT PULL] execve updates for v6.8-rc1

[Kees Cook]

On Tue, Jan 09, 2024 at 06:21:26PM -0800, Josh Triplett wrote:
> With Linus's fastpath patch ("no patch" with Linus's applied, and the
> followup -ENOMEM fix applied):
> 
> === With only PATH ===
> 0.28user 2.44system 0:02.80elapsed 97%CPU (0avgtext+0avgdata 1152maxresident)k
> 0inputs+0outputs (0major+694706minor)pagefaults 0swaps
> 
> === With 64 extra environment variables ===
> 0.29user 2.68system 0:03.06elapsed 97%CPU (0avgtext+0avgdata 1152maxresident)k
> 0inputs+0outputs (0major+712431minor)pagefaults 0swaps

Thanks for digging into this!

I've been trying to figure out how to measure only the execve portion of
a workload (with perf)[1] to get a more real-world measurement, but the
above does show improvements for the "open once early". I'll get the
behavior landed in -next after the merge window closes, and we can
continue examining if we can make do_filp_open() better...

-Kees

[1] https://lore.kernel.org/linux-perf-users/ZZ32p0LRSt5-vFPX@xxxxxxxxxx/

-- 
Kees Cook