Re: [ACPI] Re: [PATCH] s4bios for 2.5.59 + apci-20030123

[Pavel Machek <pavel@ucw.cz>]

Hi!

> Machine 1: Celeron 933 laptop 17MB/s disk throughput, 128MB RAM
> Machine 2: Duron 700 desktop, 30MB/s disk throughput, 320MB RAM
> 
> Algorithm 1: Eat as much memory as possible, save remaining in one set
> of pages
> Algorithm 2: Save memory in two pages, only eating memory if necessary.
> 
> Same code base, just different parameters to /proc/sys/kernel/swsusp.
> This means that the result for algorithm 1 are exactly the same as
> Pavel's code, but should give some idea.
> 
> Columns:
> (1) Machine
> (2) Algorithm
> (3) Initial # pages free
> (4) Image size written to disk
> (5) Approximate time taken (date command run on other computer at same
> time as pressing enter to start command, then when computer restarts)
> 
> 1  2  3           4     5
> ---------------------------------
> 1  1  25655/30592  1562 0:07
> 1  2  26246/30592  4302 0:05

You can suspend and resume your notebook within 5 seconds? Wow!

> 1  1   1005/30592  5165 0:20
> 1  2    900/30592 30126 0:16
> 2  1  38604/79755     ? 0:49
> 2  2  39122/79755 30398 0:21
> 2  1   1113/79755     ? 0:50
> 2  2   1109/79755 82149 0:40
> 
> The question marks are because the desktop machine didn't successfully
> resume using this algorithm, so stats weren't logged (probably driver
> problems).
> 
> In each case, the new method is slightly faster than the old, so we don't seem to loose anything.
> Particularly interesting to me was the fact that the gain was not as
> high as we might expect when the memory was heavily used. I guess the
> amount of I/O is getting to the point where benefits from not eating
> pages are being erroded. It would be interesting to see if a machine
> with more memory readed a point where it was faster to eat the memory
> instead of write it.

Well, if all the memory is in disk-backed clean pages, it should be
faster to discard then write out...

Anyway... So your method is faster. Good. Now, how much more
complicated is it?
								Pavel
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