From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Steven Noonan <steven@uplinklabs.net>,
kernel@collabora.com
Subject: Re: Direct rdtsc call side-effect
Date: Thu, 01 Jun 2023 12:31:22 +0200 [thread overview]
Message-ID: <87jzwneao5.ffs@tglx> (raw)
In-Reply-To: <20230601085602.GR4253@hirez.programming.kicks-ass.net>
On Thu, Jun 01 2023 at 10:56, Peter Zijlstra wrote:
> On Thu, Jun 01, 2023 at 01:45:35PM +0500, Muhammad Usama Anjum wrote:
>> We are thinking of saving and restoring the timestamp counter at suspend
>> and resume time respectively. In theory it can work on Intel because of
>> TSC_ADJUST register. But it'll never work on AMD until:
>> * AMD supports the same kind of adjust register. (AMD has said that the
>> adjust register cannot be implemented in their firmware. They'll have to
>> add it to their hardware.)
>> * by manual synchronization in kernel (I know you don't like this idea. But
>> there is something Windows is doing to save/restore and sync the TSC)
>
> Wine could set TIF_NOTSC, which will cause it to run with CR4.TSD
> cleared and cause RDTSC to #GP, at which point you can emulate it.
We should ask Microsoft to do the same. That'll fix the direct RDTSC
usage quickly. :)
next prev parent reply other threads:[~2023-06-01 10:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-01 8:45 Direct rdtsc call side-effect Muhammad Usama Anjum
2023-06-01 8:56 ` Peter Zijlstra
2023-06-01 8:58 ` Peter Zijlstra
2023-06-01 10:31 ` Thomas Gleixner [this message]
2023-06-01 10:26 ` Thomas Gleixner
2023-06-01 18:20 ` Thomas Gleixner
2023-06-01 19:07 ` Steven Noonan
2023-06-01 19:31 ` H. Peter Anvin
2023-06-01 20:10 ` Thomas Gleixner
2023-06-01 20:13 ` Thomas Gleixner
2023-06-01 20:31 ` Peter Zijlstra
2023-06-01 21:41 ` Steven Noonan
2023-06-02 6:45 ` Peter Zijlstra
2023-06-05 10:27 ` David Laight
2023-06-05 14:43 ` Thomas Gleixner
2023-06-05 15:54 ` David Laight
2023-06-05 16:32 ` H. Peter Anvin
2023-06-06 8:23 ` David Laight
2023-06-09 0:14 ` 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=87jzwneao5.ffs@tglx \
--to=tglx@linutronix.de \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=gpiccoli@igalia.com \
--cc=hpa@zytor.com \
--cc=kernel@collabora.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=steven@uplinklabs.net \
--cc=usama.anjum@collabora.com \
--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.