From: Collin Funk <collin.funk1@gmail.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] groups: Use bsearch instead of hand rolled implementation
Date: Mon, 26 May 2025 10:46:03 -0700 [thread overview]
Message-ID: <87jz63jmec.fsf@gmail.com> (raw)
In-Reply-To: <20250526002519.GX2023217@ZenIV>
Hi Al,
Al Viro <viro@zeniv.linux.org.uk> writes:
> Careful - that really needs profiling with setups where processes have
> a bunch of supplementary groups.
>
> It *is* on hot paths, and while the current version will be inlined,
> yours will do a bunch of indirect calls. These days that can be
> costly.
Sure, makes sense.
I would assume that gid_cmp/gid_lt/gid_gt all get inlined no matter
what, but I am not sure if the conversion to 'grp' to a void pointer for
the generic bsearch prevents some optimizations.
> Reducing code duplication is a good thing, but not when it creates
> measurable regressions...
Yes, that makes sense.
There is '__inline_bsearch', but I'll have to do some expirementing to
make sure that gets optimized well.
Thanks,
Collin
prev parent reply other threads:[~2025-05-26 17:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-26 0:17 Collin Funk
2025-05-26 0:25 ` Al Viro
2025-05-26 17:46 ` Collin Funk [this message]
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