All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andi Kleen <ak@linux.intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [patch V2 00/12] cpu/hotplug: SMT control
Date: Thu, 7 Jun 2018 13:36:13 -0700	[thread overview]
Message-ID: <20180607203613.GF7220@tassilo.jf.intel.com> (raw)
In-Reply-To: <nycvar.YFH.7.76.1806070939080.6203@cbobk.fhfr.pm>

On Thu, Jun 07, 2018 at 09:42:35AM +0200, speck for Jiri Kosina wrote:
> On Thu, 7 Jun 2018, speck for Thomas Gleixner wrote:
> 
> > > I still think it's pointless to add so much kernel code for something
> > > that can be done with a straight forward user script at run time
> > > using existing APIs.
> > > 
> > > We need strong justifications to add new kernel APIs.
> > > 
> > > https://raw.githubusercontent.com/andikleen/pmu-tools/master/cputop.py
> > 
> > It can be done with 3 lines of bash as well.
> > 
> > But it does neither work from the kernel command line nor does it provide
> > protections against re-online nor full enforcement. 
> > 
> > Sure it adds the massive amount of 225 lines including comments and
> > Documentation, but it's straight forward and works and has it's merits as a
> > conveniance/testing mechanism as well.
> 
> In addition to that, form a purely distro-centric POV: how exactly would 
> you envision this script to be shipped to the world (as we'll have to have 
> way to distribute it reliably to all the 'untrusted VM' providers at 
> least). Creating a separate 'smt-disable' package just for this seems like 
> an overkill, OTOH everybody has a process in place how to tweak kernel 
> cmdline / sysfs parameters.

I would add the script to tools/*

It could be added to one of the existing packages that package software
from there, and then you recommend those who actually run untrusted
VMs to use it. Most likely it's more complicated than just tweaking
the command line anyways, because likely you only want it on a subset
of the cores

I spent some time now rewriting my script to C as a "smtctl" and it could be
easily packaged in tools/*

-Andi

  reply	other threads:[~2018-06-07 20:36 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-06 19:27 [patch V2 00/12] cpu/hotplug: SMT control Thomas Gleixner
2018-06-06 19:27 ` [patch V2 01/12] sched/smt: Update sched_smt_present at runtime Thomas Gleixner
2018-06-11 18:35   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-15 13:17     ` Thomas Gleixner
2018-06-21 11:22     ` [MODERATED] " Peter Zijlstra
2018-06-06 19:27 ` [patch V2 02/12] x86/smp: Provide topology_is_primary_thread() Thomas Gleixner
2018-06-11 19:32   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-11 20:15     ` Konrad Rzeszutek Wilk
2018-06-12 10:27       ` Andrew Cooper
2018-06-12  8:05     ` Thomas Gleixner
2018-06-12 10:31       ` [MODERATED] " Andrew Cooper
2018-06-12 20:02         ` Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 03/12] cpu/hotplug: Make bringup/teardown of smp threads symmetric Thomas Gleixner
2018-06-11 20:55   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 04/12] cpu/hotplug: Split do_cpu_down() Thomas Gleixner
2018-06-11 20:56   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 05/12] cpu/hotplug: Provide knob to control SMT Thomas Gleixner
2018-06-11 21:22   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-20 20:00   ` Dave Hansen
2018-06-20 20:11     ` Thomas Gleixner
2018-06-20 20:25   ` [MODERATED] " Dave Hansen
2018-06-20 20:52     ` Thomas Gleixner
2018-06-06 19:27 ` [patch V2 06/12] x86/cpu: Remove the pointless CPU printout Thomas Gleixner
2018-06-11 21:23   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 07/12] x86/cpu/AMD: Remove the pointless detect_ht() call Thomas Gleixner
2018-06-11 21:24   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 08/12] x86/cpu/common: Provide detect_ht_early() Thomas Gleixner
2018-06-12 20:22   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 09/12] x86/cpu/topology: Provide detect_extended_topology_early() Thomas Gleixner
2018-06-12 20:33   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-06 19:27 ` [patch V2 10/12] x86/cpu/intel: Evaluate smp_num_siblings early Thomas Gleixner
2018-06-12 20:44   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-15 14:02     ` Thomas Gleixner
2018-06-06 19:27 ` [patch V2 11/12] x86/cpu/AMD: " Thomas Gleixner
2018-06-06 19:27 ` [patch V2 12/12] x86/apic: Ignore secondary threads if nosmt=force Thomas Gleixner
2018-06-06 19:59   ` [MODERATED] " Linus Torvalds
2018-06-06 21:50     ` Thomas Gleixner
2018-06-12 20:51   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-06-15 14:11     ` Thomas Gleixner
2018-06-06 23:16 ` [MODERATED] Re: [patch V2 00/12] cpu/hotplug: SMT control Andi Kleen
2018-06-07  6:50   ` Thomas Gleixner
2018-06-07  7:42     ` [MODERATED] " Jiri Kosina
2018-06-07 20:36       ` Andi Kleen [this message]
2018-06-07 20:42     ` Andi Kleen
2018-06-07 15:30 ` Konrad Rzeszutek Wilk
2018-06-07 15:43   ` Thomas Gleixner
2018-06-08 17:51 ` [MODERATED] " Josh Poimboeuf
2018-06-11 19:40 ` Jiri Kosina

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=20180607203613.GF7220@tassilo.jf.intel.com \
    --to=ak@linux.intel.com \
    --cc=speck@linutronix.de \
    /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.