Re: [PATCH][RFC] swsusp: speed up image restoring on x86-64

[Rafael J. Wysocki]

On Thursday, 20 of January 2005 21:59, Pavel Machek wrote:
> Hi!
> 
> > The following patch speeds up the restoring of swsusp images on x86-64
> > and makes the assembly code more readable (tested and works on AMD64).  It's
> > against 2.6.11-rc1-mm1, but applies to 2.6.11-rc1-mm2.  Please consifer for applying.
> 
> Can you really measure the speedup?

In terms of time?  Probably I can, but I prefer to measure it in terms of the numbers of
operations to be performed.

With this patch, at least 8 times less memory accesses are required to restore an image
than without it, and in the original code cr3 is reloaded after copying each _byte_,
let alone the SIB arithmetics.  I'd expect it to be 10 times faster or so.

The readability of code is also important, IMHO.

> If you want cheap way to speed it up, kill cr3 manipulation.

Sure, but I think it's there for a reason.

> Anyway, this is likely to clash with hugang's work; I'd prefer this not to be applied.

I am aware of that, but you are not going to merge the hugang's patches soon, are you?
If necessary, I can change the patch to work with his code (hugang, what do you think?).

Greets,
RJW


-- 
- Would you tell me, please, which way I ought to go from here?
- That depends a good deal on where you want to get to.
		-- Lewis Carroll "Alice's Adventures in Wonderland"
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