All of lore.kernel.org
 help / color / mirror / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: Dave Hansen via Libc-alpha <libc-alpha@sourceware.org>
Cc: Len Brown <lenb@kernel.org>, Dave Hansen <dave.hansen@intel.com>,
	Rich Felker <dalias@libc.org>,
	Linux API <linux-api@vger.kernel.org>,
	"Bae, Chang Seok" <chang.seok.bae@intel.com>,
	X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
	Kyle Huey <me@kylehuey.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Keno Fischer <keno@juliacomputing.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Willy Tarreau <w@1wt.eu>
Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features
Date: Fri, 21 May 2021 16:44:58 +0200	[thread overview]
Message-ID: <87pmxk87th.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: 9c8138eb-3956-e897-ed4e-426bf6663c11@intel.com

* Dave Hansen via Libc-alpha:

> Our system calls are *REALLY* fast.  We can even do a vsyscall for this
> if we want to get the overhead down near zero.  Userspace can also cache
> the "I did the prctl()" state in thread-local storage if it wants to
> avoid the syscall.

Why can't userspace look at XCR0 to make the decision?

And we added an interface for querying x86 CPU features to glibc 2.33
which is completely incompatible with this because it assumes that CPU
features do not change during the lifetime of a process. 8-(

Thanks,
Florian


  parent reply	other threads:[~2021-05-21 14:45 UTC|newest]

Thread overview: 130+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 23:12 Candidate Linux ABI for Intel AMX and hypothetical new related features Andy Lutomirski
2021-03-26 23:18 ` Andy Lutomirski
2021-03-27  3:39   ` Len Brown
2021-03-27  9:14     ` Borislav Petkov
2021-03-27  9:58     ` Greg KH
2021-03-29 15:47       ` Len Brown
2021-03-29 16:38         ` Len Brown
2021-03-29 16:48           ` Florian Weimer
2021-03-29 18:14           ` Andy Lutomirski
2021-03-29 18:16         ` Andy Lutomirski
2021-03-29 22:38           ` Len Brown
2021-03-30  5:08             ` Andy Lutomirski
2021-03-30  5:50               ` Noah Goldstein
2021-03-30 17:01               ` Len Brown
2021-03-30 17:05                 ` Andy Lutomirski
2021-03-30 17:56                   ` Len Brown
2021-03-30 19:12                     ` Dave Hansen
2021-03-30 20:20                       ` Andy Lutomirski
2021-03-30 20:42                         ` Len Brown
2021-03-30 22:01                           ` David Laight
2021-03-31 16:31                             ` Len Brown
2021-03-31 16:53                               ` Andy Lutomirski
2021-03-31 21:42                                 ` Robert O'Callahan
2021-03-31 22:11                                   ` Len Brown
2021-03-31 22:28                                 ` Len Brown
2021-03-31 22:45                                   ` Andy Lutomirski
2021-04-09 20:52                                     ` Len Brown
2021-04-09 21:44                                       ` Andy Lutomirski
2021-04-11 19:07                                         ` Len Brown
2021-04-12  7:59                                           ` David Laight
2021-04-12 12:19                                           ` Borislav Petkov
2021-04-12 17:14                                           ` Sean Christopherson
2021-03-31 22:52                                   ` Borislav Petkov
2021-04-09 20:55                                     ` Len Brown
2021-03-28  0:53   ` Thomas Gleixner
2021-03-29  7:27     ` Peter Zijlstra
2021-03-29 15:06     ` Dave Hansen
2021-03-31  8:24 ` Borislav Petkov
     [not found] ` <87lf9nk2ku.fsf@oldenburg.str.redhat.com>
2021-04-12 14:31   ` Borislav Petkov
2021-04-12 14:38     ` Florian Weimer
2021-04-12 15:08       ` Borislav Petkov
2021-04-12 15:10       ` Andy Lutomirski
2021-04-12 15:21   ` Andy Lutomirski
2021-04-12 23:46     ` Len Brown
2021-04-13  0:17       ` Thomas Gleixner
2021-04-13  1:25         ` Len Brown
2021-04-13  3:43       ` Willy Tarreau
2021-04-13 19:51         ` Len Brown
2021-04-14  9:58           ` Borislav Petkov
2021-04-14 10:06             ` Willy Tarreau
2021-04-14 10:08               ` Borislav Petkov
2021-04-14 21:57             ` Len Brown
2021-04-15  4:43               ` Borislav Petkov
2021-04-15  5:29                 ` Willy Tarreau
2021-04-15  5:47                   ` Borislav Petkov
2021-04-16 22:05                     ` Len Brown
2021-04-19 14:14                       ` Borislav Petkov
2021-04-19 18:18                         ` Len Brown
2021-04-19 19:15                           ` Borislav Petkov
2021-04-19 21:33                             ` Len Brown
2021-04-19 21:58                               ` Borislav Petkov
2021-04-23 19:35                                 ` Len Brown
2021-04-23 19:57                                   ` Borislav Petkov
2021-05-02 15:27                                     ` Len Brown
2021-05-03  5:18                                       ` Florian Weimer
2021-05-03 13:43                                         ` Dave Hansen
2021-05-03 13:47                                           ` Florian Weimer
2021-05-03 14:14                                             ` Dave Hansen
2021-05-07 18:44                                           ` Thomas Gleixner
2021-05-07 18:50                                             ` Andy Lutomirski
2021-05-07 19:22                                               ` Thomas Gleixner
2021-05-08  9:45                                       ` Thomas Gleixner
2021-05-18 20:39                                         ` Len Brown
2021-05-19 23:29                                           ` Andy Lutomirski
2021-05-20 19:16                                             ` Len Brown
2021-05-17  9:45                                       ` Thomas Gleixner
2021-05-17  9:56                                         ` Florian Weimer
2021-05-17 10:18                                           ` Thomas Gleixner
2021-05-21 16:29                                           ` Len Brown
2021-05-17 13:49                                         ` Arjan van de Ven
2021-05-20 15:35                                         ` Len Brown
2021-05-20 20:54                                           ` Thomas Gleixner
2021-05-20 21:13                                             ` Dave Hansen
2021-05-20 21:41                                               ` Len Brown
2021-05-20 22:53                                                 ` Dave Hansen
2021-05-21  9:41                                                   ` Thomas Gleixner
2021-05-21 14:44                                                   ` Florian Weimer [this message]
2021-05-21 14:49                                                     ` Peter Zijlstra
2021-06-23 15:06                                                       ` Florian Weimer
2021-06-23 23:11                                                         ` Len Brown
2021-06-28 10:14                                                           ` Enrico Weigelt, metux IT consult
2021-06-28 12:49                                                             ` Florian Weimer
2021-06-30 12:22                                                               ` Enrico Weigelt, metux IT consult
2021-06-30 12:41                                                                 ` Willy Tarreau
2021-06-30 13:55                                                                 ` Arjan van de Ven
2021-06-30 15:20                                                                   ` Len Brown
2021-06-30 15:25                                                                   ` Enrico Weigelt, metux IT consult
2021-05-21 16:14                                                     ` Dave Hansen
2021-05-21 16:19                                                       ` Florian Weimer
2021-05-21 16:26                                                         ` Len Brown
2021-05-21 16:28                                                         ` Dave Hansen
2021-05-21 16:31                                                         ` Andy Lutomirski
2021-05-21 19:10                                                           ` Thomas Gleixner
2021-05-21 20:07                                                             ` Andy Lutomirski
2021-05-21 21:43                                                               ` Thomas Gleixner
2021-05-21 22:07                                                             ` Len Brown
2021-05-21 22:46                                                               ` Thomas Gleixner
2021-05-21 23:31                                                                 ` Len Brown
2021-05-22  7:16                                                                   ` Florian Weimer
2021-05-22 23:55                                                                     ` Andy Lutomirski
2021-05-21 23:06                                                               ` Dave Hansen
2021-05-21 23:08                                                                 ` Len Brown
2021-05-21 19:05                                                         ` Thomas Gleixner
2021-05-20 21:22                                             ` Len Brown
2021-05-20 21:41                                               ` Thomas Gleixner
2021-05-20 21:49                                                 ` Len Brown
2021-05-21  9:26                                                   ` Thomas Gleixner
2021-04-19 23:52                               ` Paul Eggert
2021-04-13 20:16       ` Andy Lutomirski
2021-04-13 22:47         ` Len Brown
2021-04-13 22:58           ` Andy Lutomirski
2021-04-14 21:48             ` Len Brown
2021-04-15 16:24               ` Andy Lutomirski
2021-04-15 17:00                 ` Dave Hansen
2021-04-15 17:38                   ` Andy Lutomirski
2021-04-16 21:54                 ` Len Brown
2021-04-16 22:03                   ` Andy Lutomirski
2021-04-16 22:10                     ` Len Brown
2021-04-16 22:14                       ` Andy Lutomirski
2021-04-17  1:57                         ` Len Brown

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=87pmxk87th.fsf@oldenburg.str.redhat.com \
    --to=fweimer@redhat.com \
    --cc=arjan@linux.intel.com \
    --cc=bp@alien8.de \
    --cc=chang.seok.bae@intel.com \
    --cc=dalias@libc.org \
    --cc=dave.hansen@intel.com \
    --cc=keno@juliacomputing.com \
    --cc=lenb@kernel.org \
    --cc=libc-alpha@sourceware.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=me@kylehuey.com \
    --cc=tglx@linutronix.de \
    --cc=w@1wt.eu \
    --cc=x86@kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.