From: Sergey Bugaev <bugaevc@gmail.com>
To: Samuel Thibault <samuel.thibault@gnu.org>
Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org
Subject: Re: [PATCH 3/4] hurd: Microoptimize mmap ()
Date: Tue, 25 Apr 2023 00:09:58 +0300 [thread overview]
Message-ID: <CAN9u=HcHkt0pggx9ps-oQfvWXnegsrhoW9DQABP8yrPEp4ZFkQ@mail.gmail.com> (raw)
In-Reply-To: <20230424204644.omudvkhihy3nzj7m@begin>
On Mon, Apr 24, 2023 at 11:47 PM Samuel Thibault
<samuel.thibault@gnu.org> wrote:
> Is it really worth making the code a bit obscure?
No, not really.
What happened here was I looked at what my mask computation compiled
to, to verify it does the right thing on both x86_64 and i686, and
then I saw how the error branches are compiled, and next thing you
know there are new __glibc_unlikely's in my tree :)
What I should rather look into is marking __hurd_fail and friends with
__attribute__((cold)); that would take care of all the error branches
everywhere automatically without having to mark things up. But I did a
quick grep and found nothing using __attribute__((cold)) yet, so I
don't know what the right way of using it would be (and maybe it's not
being used intentionally?). I'm thinking it should probably go into
misc/sys/cdefs.h as __COLD (or __attribute_cold?). Something like
this:
#if __glibc_has_attribute (cold)
#define __COLD __attribute__ ((cold))
#else
#define __COLD
#endif
What do you think?
Sergey
next prev parent reply other threads:[~2023-04-24 21:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-23 21:55 [PATCH 1/4] hurd: Implement MAP_32BIT Sergey Bugaev
2023-04-23 21:55 ` [PATCH 2/4] hurd: Don't attempt to deallocate MACH_PORT_DEAD Sergey Bugaev
2023-04-24 20:44 ` Samuel Thibault
2023-04-23 21:55 ` [PATCH 3/4] hurd: Microoptimize mmap () Sergey Bugaev
2023-04-24 20:46 ` Samuel Thibault
2023-04-24 21:09 ` Sergey Bugaev [this message]
2023-04-24 21:25 ` Samuel Thibault
2023-04-23 21:55 ` [RFC PATCH 4/4] hurd: Implement prefer_map_32bit_exec tunable Sergey Bugaev
2023-04-24 20:48 ` Samuel Thibault
2023-04-24 20:42 ` [PATCH 1/4] hurd: Implement MAP_32BIT Samuel Thibault
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