From: Andy Lutomirski <luto@amacapital.net>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Sasha Levin <sasha.levin@oracle.com>,
Stefani Seibold <stefani@seibold.net>,
Thomas Gleixner <tglx@linutronix.de>,
Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [GIT PULL] x86/vdso changes for v3.16
Date: Fri, 6 Jun 2014 14:44:51 -0700 [thread overview]
Message-ID: <CALCETrXoveOV5qoQ0vBcLiZ15BXAyEiL+oWUWrHKOXuui-Cspg@mail.gmail.com> (raw)
In-Reply-To: <539235C5.1030002@zytor.com>
On Fri, Jun 6, 2014 at 2:42 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 06/06/2014 02:39 PM, Andy Lutomirski wrote:
>>>
>>> For accessing memory members doing it via a pointer is pretty much TRT,
>>> but for things that might be in register it is undesirable to force it
>>> out to memory.
>>
>> Do you also believe in the folklore that GCC can optimize code
>> sequences like the things in that header? Because I'm pretty sure
>> that no clang or gcc version I've ever seen can do it.
>>
>
> I have seen gcc do some pretty sophisticated memory elision lately.
> Don't know if that includes byte swaps.
>
>> On the other hand, even a factor of ten in the time it takes to run
>> vdso2c is completely irrelevant.
>
> Yep, as I noted in the patch I sent (which is broken - updated one
> included here.)
Acked-by: Andy Lutomirski <luto@amacapital.net>
The generated vdso-image-*.c files are identical.
--Andy
>
> -hpa
>
--
Andy Lutomirski
AMA Capital Management, LLC
next prev parent reply other threads:[~2014-06-06 21:45 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-04 22:35 [GIT PULL] x86/vdso changes for v3.16 H. Peter Anvin
2014-06-06 21:00 ` Andrew Morton
2014-06-06 21:07 ` H. Peter Anvin
2014-06-08 17:18 ` Sam Ravnborg
2014-06-08 18:54 ` H. Peter Anvin
2014-06-06 21:07 ` Linus Torvalds
2014-06-06 21:09 ` Andy Lutomirski
2014-06-06 21:13 ` Linus Torvalds
2014-06-06 21:14 ` Andy Lutomirski
2014-06-06 21:15 ` H. Peter Anvin
2014-06-06 21:22 ` Andy Lutomirski
2014-06-06 21:25 ` H. Peter Anvin
2014-06-06 21:33 ` Andy Lutomirski
2014-06-06 21:37 ` H. Peter Anvin
2014-06-06 21:39 ` Andy Lutomirski
2014-06-06 21:42 ` H. Peter Anvin
2014-06-06 21:44 ` Andy Lutomirski [this message]
2014-06-06 21:36 ` H. Peter Anvin
2014-06-06 22:00 ` [tip:x86/vdso] x86, vdso: Use <tools/le_byteshift.h> for littleendian access tip-bot for H. Peter Anvin
2014-06-10 20:50 ` Andrew Morton
2014-06-10 21:28 ` H. Peter Anvin
2014-06-10 21:35 ` Andy Lutomirski
2014-06-10 22:06 ` Andrew Morton
2014-06-10 22:43 ` [tip:x86/vdso] x86, vdso: Remove one final use of htole16() tip-bot for H. Peter Anvin
2014-06-10 22:57 ` tip-bot for H. Peter Anvin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CALCETrXoveOV5qoQ0vBcLiZ15BXAyEiL+oWUWrHKOXuui-Cspg@mail.gmail.com \
--to=luto@amacapital.net \
--cc=akpm@linux-foundation.org \
--cc=gorcunov@openvz.org \
--cc=hpa@linux.intel.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=sasha.levin@oracle.com \
--cc=stefani@seibold.net \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=xemul@parallels.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).