From: Denys Vlasenko <dvlasenk@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Andy Lutomirski" <luto@amacapital.net>,
"Sara Sharon" <sara.sharon@intel.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Christian König" <christian.koenig@amd.com>,
"Vinod Koul" <vinod.koul@intel.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Johannes Berg" <johannes.berg@intel.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
"Andy Lutomirski" <luto@kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Ingo Molnar" <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Adrian Hunter" <adrian.hunter@intel.com>
Subject: Re: RFC: Petition Intel/AMD to add POPF_IF insn
Date: Thu, 18 Aug 2016 19:49:10 +0200 [thread overview]
Message-ID: <f7123992-8173-67fc-b79f-bebc98abb123@redhat.com> (raw)
In-Reply-To: <d49cfa3e-f5d3-07fd-6e5d-573b37b66824@redhat.com>
On 08/18/2016 07:47 PM, Denys Vlasenko wrote:
> On 08/18/2016 07:24 PM, Linus Torvalds wrote:
>> That said, your numbers really aren't very convincing. If popf really
>> is just 10 cycles on modern Intel hardware, it's already fast enough
>> that I really don't think it matters.
>
> It's 20 cycles. I was wrong in my email, I forgot that the insn count
> also counts "push %ebx" insns.
>
> Since I already made a mistake, let me double-check.
>
> 200 million iterations of this loop execute under 17 seconds:
>
> 400100: b8 00 c2 eb 0b mov $0xbebc200,%eax # 1000*1000*1000
Grr. It's 200*1000*1000, not one billion. Sorry.
next prev parent reply other threads:[~2016-08-19 0:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 17:20 Denys Vlasenko
2016-08-17 17:30 ` Christian König
2016-08-17 18:34 ` Denys Vlasenko
2016-08-17 17:32 ` Linus Torvalds
2016-08-17 18:41 ` Denys Vlasenko
[not found] ` <CA+55aFwmxwQBkyDjombS4cy1q=a_buhmDjDnaa8rdC8ZDaDYEA@mail.gmail.com>
2016-08-17 19:13 ` Andy Lutomirski
2016-08-17 19:26 ` Denys Vlasenko
2016-08-17 19:32 ` Linus Torvalds
2016-08-17 19:35 ` Denys Vlasenko
2016-08-17 19:54 ` Linus Torvalds
2016-08-17 19:37 ` Linus Torvalds
2016-08-17 21:26 ` Linus Torvalds
2016-08-17 21:35 ` Linus Torvalds
2016-08-17 21:43 ` Andy Lutomirski
2016-08-17 21:48 ` Linus Torvalds
2016-08-18 13:26 ` Denys Vlasenko
2016-08-18 17:24 ` Linus Torvalds
2016-08-18 17:47 ` Denys Vlasenko
2016-08-18 17:49 ` Denys Vlasenko [this message]
2016-08-19 10:54 ` Paolo Bonzini
2016-08-31 11:12 ` Denys Vlasenko
2016-08-18 9:21 ` Denys Vlasenko
2016-08-18 12:18 ` Denys Vlasenko
2016-08-18 17:22 ` Paolo Bonzini
2016-08-17 19:29 ` Linus Torvalds
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=f7123992-8173-67fc-b79f-bebc98abb123@redhat.com \
--to=dvlasenk@redhat.com \
--cc=adrian.hunter@intel.com \
--cc=alexander.deucher@amd.com \
--cc=christian.koenig@amd.com \
--cc=dan.j.williams@intel.com \
--cc=johannes.berg@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=rafael.j.wysocki@intel.com \
--cc=sara.sharon@intel.com \
--cc=torvalds@linux-foundation.org \
--cc=vinod.koul@intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®