Re: [RFC 0/2] Delay initializing of large sections of memory

From: H. Peter Anvin
Date: Fri Jun 21 2013 - 13:29:16 EST

On 06/21/2013 10:18 AM, Nathan Zimmer wrote:
>> Since you made it a compile time option, it would be good to know how
>> much code it adds, but otherwise I agree with Greg here... this really
>> shouldn't need to be an option. It *especially* shouldn't need to be a
>> hand-set runtime option (which looks quite complex, to boot.)
> The patchset as a whole is just over 400 lines so it doesn't add alot.
> If I were to pull the .config option it would probably remove 30 lines.

I'm more concerned about bytes of code.

> The command line option is too complex but some of the data I haven't
> found a way to get at runtime yet.

I think that is probably key.

>> I suspect the cutoff for this should be a lot lower than 8 TB even, more
>> like 128 GB or so. The only concern is to not set the cutoff so low
>> that we can end up running out of memory or with suboptimal NUMA
>> placement just because of this.
> Even at lower amounts of ram there is an positive impact.I it knocks
> time off
> boot even at as small as a 1TB of ram.

I am not surprised.


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