From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Pavel Machek <pavel@ucw.cz>, Joerg Roedel <joro@8bytes.org>
Cc: Len Brown <len.brown@intel.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/6 v2] PM / Hibernate: Memory bitmap scalability improvements
Date: Tue, 22 Jul 2014 02:41:29 +0200 [thread overview]
Message-ID: <6793803.1FXN0a3O0V@vostro.rjw.lan> (raw)
In-Reply-To: <20140721230500.GA7019@amd.pavel.ucw.cz>
On Tuesday, July 22, 2014 01:05:00 AM Pavel Machek wrote:
> Hi!
>
> On Mon 2014-07-21 18:03:46, Joerg Roedel wrote:
> > On Mon, Jul 21, 2014 at 04:10:27PM +0200, Pavel Machek wrote:
> > > > And Linux is only made for sane people? Thats pretty new to me ;-)
> > >
> > > Yeah, but please don't optimize for insane people :-).
> >
> > Thats rather discriminating, even more when you realize that 'insane' is
> > a very subjective attribute.
>
> You admitted you don't even have access to machine you are trying to
> optimize for.
>
> > > #6 is bugfix. We should take it. Rest is performance improvement for
> > > insane config. I don't think we should take it.
> >
> > Have you any other reason against these changes besides your
> > proven-to-be-wrong disbelief that it is necessary?
>
> Where you proven me wrong?
>
> If kernel is preparing bitmaps before checking resume signature, that
> is bug that costs you 60 seconds boot time on your 12TB machine. Fix
> that bug. It will benefit everyone.
>
> Software watchdog during hibernation on 12TB machine is a bug that
> hits insane people. Ok, lets fix it.
>
> Optimizing hibernation for memory-is-empty case is wrong. Linux tries
> to use as much memory as it can.
>
> Hibernating 12TB machine will take 5 hours or more. Redoing data
> structures to save 60 seconds of 5 hour process is not worth
> it. Nobody sane would hibernate 12TB machine.
It looks like some specific need motivated the Joerg's work, however,
so let's just not dismiss the use case lightly without knowing it.
That said I would like to know how much time we save through this
optimization relative to the total hibernation time on systems with
various amounts of memory (say, 4 GB, 8 GB, 16 GB, 32 GB, more) and
whether or not it makes hibernation slower in any case.
Rafael
next prev parent reply other threads:[~2014-07-22 0:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-21 10:26 Joerg Roedel
2014-07-21 10:26 ` [PATCH 1/6] PM / Hibernate: Create a Radix-Tree to store memory bitmap Joerg Roedel
2014-07-21 22:36 ` Joerg Roedel
2014-07-21 23:05 ` Pavel Machek
2014-07-21 10:26 ` [PATCH 2/6] PM / Hibernate: Add memory_rtree_find_bit function Joerg Roedel
2014-07-21 10:26 ` [PATCH 3/6] PM / Hibernate: Implement position keeping in radix tree Joerg Roedel
2014-07-21 10:27 ` [PATCH 4/6] PM / Hibernate: Iterate over set bits instead of PFNs in swsusp_free() Joerg Roedel
2014-07-21 10:27 ` [PATCH 5/6] PM / Hibernate: Remove the old memory-bitmap implementation Joerg Roedel
2014-07-21 10:27 ` [PATCH 6/6] PM / Hibernate: Touch Soft Lockup Watchdog in rtree_next_node Joerg Roedel
2014-07-21 12:00 ` [PATCH 0/6 v2] PM / Hibernate: Memory bitmap scalability improvements Pavel Machek
2014-07-21 12:36 ` Joerg Roedel
2014-07-21 13:06 ` Pavel Machek
2014-07-21 13:38 ` Joerg Roedel
2014-07-21 14:10 ` Pavel Machek
2014-07-21 16:03 ` Joerg Roedel
2014-07-21 23:05 ` Pavel Machek
2014-07-22 0:41 ` Rafael J. Wysocki [this message]
2014-07-22 10:34 ` Joerg Roedel
2014-07-22 10:55 ` Pavel Machek
2014-07-22 12:24 ` Joerg Roedel
2014-07-22 10:58 ` Pavel Machek
2014-07-22 12:10 ` Joerg Roedel
2014-07-23 10:57 ` Pavel Machek
2014-07-28 13:59 ` Borislav Petkov
2014-07-29 21:22 ` Rafael J. Wysocki
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=6793803.1FXN0a3O0V@vostro.rjw.lan \
--to=rjw@rjwysocki.net \
--cc=joro@8bytes.org \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=pavel@ucw.cz \
/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®