From: Andi Kleen <andi@firstfloor.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Andi Kleen <andi@firstfloor.org>
Subject: Re: [RFC] x86_64: A real proposal for iret-less return to kernel
Date: Thu, 22 May 2014 00:25:41 +0200 [thread overview]
Message-ID: <20140521222541.GO1873@two.firstfloor.org> (raw)
In-Reply-To: <CALCETrXudJ8BkNF_M-r4O40XLN+PnZ5TOZw0P7N4kqo3qngzyg@mail.gmail.com>
Seems like a lot of effort and risk to essentially only optimize in kernel
interrupt handlers.
AFAIK the most interesting cases (like user page faults) are not
affected at all. Usually most workloads don't spend all that much time
in the kernel, so it won't help most interrupts.
I suspect the only case that's really interesting here is interrupting
idle. Maybe it would be possible to do some fast path in this case only.
However idle currently has so much overhead that I suspect that there
are lower hanging fruit elsewhere.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2014-05-21 22:25 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-21 0:53 [RFC] x86_64: A real proposal for iret-less return to kernel Andy Lutomirski
2014-05-21 2:27 ` Steven Rostedt
2014-05-21 2:33 ` H. Peter Anvin
2014-05-21 2:39 ` Andy Lutomirski
2014-05-21 9:46 ` Borislav Petkov
2014-05-21 15:21 ` Andy Lutomirski
2014-05-21 16:30 ` Borislav Petkov
2014-05-21 17:52 ` Andy Lutomirski
2014-05-21 18:07 ` Borislav Petkov
2014-05-21 12:51 ` Jiri Kosina
2014-05-21 15:21 ` Andy Lutomirski
2014-05-21 16:33 ` Borislav Petkov
2014-05-21 21:25 ` Jiri Kosina
2014-05-21 21:35 ` Andy Lutomirski
2014-05-21 21:48 ` Borislav Petkov
2014-05-21 21:52 ` Andy Lutomirski
2014-05-21 21:55 ` Borislav Petkov
2014-05-21 21:59 ` Jiri Kosina
2014-05-21 21:59 ` Andy Lutomirski
2014-05-21 22:01 ` Luck, Tony
2014-05-21 22:13 ` Andy Lutomirski
2014-05-21 22:17 ` Borislav Petkov
2014-05-21 22:20 ` Andy Lutomirski
2014-05-21 22:36 ` Borislav Petkov
2014-05-21 22:18 ` Luck, Tony
2014-05-21 22:24 ` Andy Lutomirski
2014-05-21 22:32 ` Luck, Tony
2014-05-21 22:39 ` Andy Lutomirski
2014-05-21 22:48 ` Borislav Petkov
2014-05-21 22:52 ` Andy Lutomirski
2014-05-21 23:02 ` Borislav Petkov
2014-05-21 23:05 ` Luck, Tony
2014-05-21 23:07 ` Andy Lutomirski
2014-05-21 23:19 ` Luck, Tony
2014-05-21 23:30 ` Linus Torvalds
2014-05-21 23:40 ` Luck, Tony
2014-05-21 23:51 ` Borislav Petkov
2014-05-22 0:03 ` Linus Torvalds
2014-05-22 8:50 ` Borislav Petkov
2014-05-22 0:05 ` Andy Lutomirski
2014-05-21 21:37 ` Linus Torvalds
2014-05-21 21:43 ` Borislav Petkov
2014-05-21 21:45 ` H. Peter Anvin
2014-05-21 21:47 ` Andy Lutomirski
2014-05-21 21:54 ` Borislav Petkov
2014-05-21 22:00 ` H. Peter Anvin
2014-05-21 22:11 ` Borislav Petkov
2014-05-21 22:13 ` H. Peter Anvin
2014-05-21 22:21 ` Borislav Petkov
2014-05-26 10:18 ` [PATCH] x86, MCE: Flesh out when to panic comment Borislav Petkov
2014-05-26 10:51 ` Jiri Kosina
2014-05-26 11:06 ` Borislav Petkov
2014-05-26 16:47 ` Andy Lutomirski
2014-05-26 17:51 ` Borislav Petkov
2014-05-26 17:59 ` Andy Lutomirski
2014-05-27 21:53 ` Luck, Tony
2014-05-27 22:24 ` Borislav Petkov
2014-05-27 22:33 ` Luck, Tony
2014-05-21 21:50 ` [RFC] x86_64: A real proposal for iret-less return to kernel Jiri Kosina
2014-05-21 18:11 ` Andy Lutomirski
2014-05-21 22:36 ` H. Peter Anvin
2014-05-21 22:41 ` Andy Lutomirski
2014-05-21 23:03 ` H. Peter Anvin
2014-05-21 22:25 ` Andi Kleen [this message]
2014-05-21 22:32 ` Andy Lutomirski
2014-05-21 22:33 ` Linus Torvalds
2014-05-21 23:23 ` Andi Kleen
2014-05-21 23:34 ` Linus Torvalds
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