[linux-mm-cc] interbench result

[Nai Xia]

On Tue, May 13, 2008 at 1:10 PM, Nitin Gupta <nitingupta910 at gmail.com> wrote:
> On Tue, May 13, 2008 at 9:51 AM, Nai Xia <nai.xia at gmail.com> wrote:
>  > ---------- Forwarded message ----------
>  >  From: Nai Xia <nai.xia at gmail.com>
>  >  Date: Mon, May 12, 2008 at 11:58 PM
>  >  Subject: Re: [linux-mm-cc] interbench result
>  >  To: John McCabe-Dansted <gmatht at gmail.com>
>  >
>  >
>  >
>  >  On Mon, May 12, 2008 at 10:44 PM, John McCabe-Dansted <gmatht at gmail.com> wrote:
>  >   > I find the following format easier to understand, and have attached Nai's
>  >
>  >   Yes, you are right, :)
>  >
>  >
>  >
>  >   > result in this format. Additionally I have generated results for my P3-500
>  >   > with 256MB of ram and 512MB of compcache, and included the scripts I used.
>  >   >
>
>
>  >   > Anyway, Nai do you have an interpretation  of this data? Also, is the memory
>  >
>
>  Readme file included with interbench contains some information on this.
>
>
>
>  >   Well, actually I am thinking although interbench was a good
>  >   Interactivity benchmark tool,
>  >   it may not distinguish compcache much. For most of the numbers are
>  >   related to CPU timing,
>  >   but all the simulated programs do not change RAM usage when they are
>  >   waked up or sleep.
>  >   I am thinking that the result is of little relevance to the amount of
>  >   PHY RAM it has, it is designed
>  >   for scheduler.(I will do additional test to prove this).
>  >
>
>  Yes, now I also think the same. After interbench tests are completed,
>  very little swap
>  space is used. So, it is not much afftected by compcache.
>
>
>  >   By now, from my point of view, what we really need is a
>  >   famous/standard benchmark that makes anonymous pages compete
>  >   drastically with file cached pages (like kpdf & firefox )---- that is
>  >   indeed where compcache stands like a real hero.
>  >
>
>  I think ideal scenario for compcache is when all of these conditions
>  are satisfied:
>   - Working set of apps (anon + page cache) > Physical RAM
>   - Phy RAM left over from compcache is enough to hold page-cache part
>  of working set
>   - Compressibility is good
>
>  These conditions seem to hold true for "general desktop use" (web
>  browsers, editors etc.)

So, any suggestions for what we do next ? :)


>
>
>  >
>  >
>  >
>  >   > used in any sense of "normal" compressibility?
>  >
>  >   I did not record the compressibility, since I thought intercepting
>  >   interbench might change the result .....
>  >
>  >
>
>  You can note this by checking /proc/compcache after interbench tests
>  are complete.

Yes, that's the overall stat info. So I thought it might be hard to
get the memory behavior of interbench at each step or each time
interval.......

>  In my tests, I see that compressibility is great (NumGoodCompress > 95%) since
>  maybe its filling memory with 0's. One strange thing to notice is that number

Actually they are 1's :)

>  of ramzswap reads/writes is huge (in order of 10^6).

I bet it's memload. The comment above the while(1) loop in
emulate_memload() in interbench.c says /* loop until we're
killed...*/,  it's violent.

>
>
>  Cheers,
>  Nitin
>