From: Rik van Riel <riel@surriel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Mike Galbraith <efault@gmx.de>,
songliubraving@fb.com, kernel-team <kernel-team@fb.com>
Subject: Re: [PATCH 7/7] x86,idle: do not leave mm in idle state
Date: Fri, 22 Jun 2018 16:18:59 -0400 [thread overview]
Message-ID: <1529698739.7898.206.camel@surriel.com> (raw)
In-Reply-To: <CALCETrXJzhwXkEi5oC9XY58B8fYT26WhMT+KBt-8m2M+foQvsw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 989 bytes --]
On Fri, 2018-06-22 at 09:01 -0700, Andy Lutomirski wrote:
> Hmm, fair enough. I think a better heuristic would be if the
> estimated idle duration is more than, say, 10ms. I *think* the code
> has been cleaned up enough that this is easy now. (Using time
> instead
> of C6 will make it a lot less dependent on which idle driver is in
> use.)
This particular bit of code is only in intel_idle
though, and not every cpuidle governor estimates
an idle duration, nor does it get passed up the
stack (presumably because it not always exists).
I will just drop this patch for now, and see if
adding back in the patch that skips manipulation
of the mm_cpumask(&init_mm), since that might make
leave_mm() a little cheaper.
We would still have excess manipulation of the
bitmask when re-entering the task from what should
have been lazy TLB mode, but total cache line
contention would likely still be down from where
it is before that patch.
--
All Rights Reversed.
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2018-06-22 20:19 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 19:56 [PATCH 0/7] x86,tlb,mm: make lazy TLB mode even lazier Rik van Riel
2018-06-20 19:56 ` [PATCH 1/7] mm: allocate mm_cpumask dynamically based on nr_cpu_ids Rik van Riel
2018-06-20 21:32 ` kbuild test robot
2018-06-21 20:18 ` Rik van Riel
2018-06-21 0:24 ` kbuild test robot
2018-06-22 15:10 ` Dave Hansen
2018-06-22 17:45 ` Rik van Riel
2018-06-20 19:56 ` [PATCH 2/7] x86,tlb: leave lazy TLB mode at page table free time Rik van Riel
2018-06-21 0:23 ` Rik van Riel
2018-06-22 14:58 ` Andy Lutomirski
2018-06-22 15:17 ` Rik van Riel
2018-06-20 19:56 ` [PATCH 3/7] x86,tlb: change tlbstate.is_lazy to tlbstate.state Rik van Riel
2018-06-22 17:01 ` Dave Hansen
2018-06-22 17:08 ` Rik van Riel
2018-06-20 19:56 ` [PATCH 4/7] x86,tlb: make lazy TLB mode lazier Rik van Riel
2018-06-22 15:04 ` Andy Lutomirski
2018-06-22 15:15 ` Rik van Riel
2018-06-22 15:34 ` Andy Lutomirski
2018-06-22 17:05 ` Dave Hansen
2018-06-22 17:16 ` Rik van Riel
2018-06-20 19:56 ` [PATCH 5/7] x86,tlb: only send page table free TLB flush to lazy TLB CPUs Rik van Riel
2018-06-22 17:23 ` Dave Hansen
2018-06-20 19:56 ` [PATCH 6/7] x86,mm: always use lazy TLB mode Rik van Riel
2018-06-20 19:56 ` [PATCH 7/7] x86,idle: do not leave mm in idle state Rik van Riel
2018-06-20 22:20 ` kbuild test robot
2018-06-21 0:25 ` Rik van Riel
2018-06-22 15:36 ` Andy Lutomirski
2018-06-22 15:53 ` Rik van Riel
2018-06-22 16:01 ` Andy Lutomirski
2018-06-22 20:18 ` Rik van Riel [this message]
2018-06-22 22:05 ` Andy Lutomirski
2018-06-23 0:55 ` Rik van Riel
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=1529698739.7898.206.camel@surriel.com \
--to=riel@surriel.com \
--cc=dave.hansen@linux.intel.com \
--cc=efault@gmx.de \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=songliubraving@fb.com \
--cc=tglx@linutronix.de \
--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;
as well as URLs for NNTP newsgroup(s).