Re: [PATCH 00/14] Pramfs: Persistent and protected ram filesystem

Pavel Machek
2009-07-10T12:28:21Z

On Sun 2009-06-28 19:33:02, Marco Stornelli wrote:
> Pavel Machek wrote:
> >>>>> Ah now the write protection is a "needed feature", in your previous
> >>>>> comment you talked about why not use ext2/3.......
> >>>>>
> >>>>> Marco
> >>>>>
> >>>> Just for your information I tried the same test with pc in a virtual machine with 32MB of RAM:
> >>>>
> >>>> Version 1.03e ------Sequential Output------ --Sequential Input- --Random-
> >>>> -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
> >>>> Machine Size:chnk K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
> >>>> hostname 15M:1k 14156 99 128779 100 92240 100 11669 100 166242 99 80058 82
> >>>> ------Sequential Create------ --------Random Create--------
> >>>> -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
> >>>> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
> >>>> 4 2842 99 133506 104 45088 101 2787 99 79581 101 58212 102
> >>>>
> >>>> These data are the proof of the importance of the environment, workload and so on when we talk
> >>>> about benchmark. Your consideration are really superficial.
> >>> Unfortunately, your numbers are meaningless.
> >> I don't think so.
> >>
> >>> (PCs should have cca 3GB/sec RAM transfer rates; and you demosstrated
> >>> cca 166MB/sec read rate; disk is 80MB/sec, so that's too slow. If you
> >>> want to prove your filesystem the filesystem is reasonably fast,
> >>> compare it with ext2 on ramdisk.)
> >>>
> >> This is the point. I don't want compare it with ext2 from performance
> >> point of view. This comparison makes no sense for me. I've done this
> >> test to prove that if you change environment you can change in a
> >> purposeful way the results.
> >
> > Yes, IOW you demonstrated that the numbers are machine-dependend and
> > really meaningless.
> >
> > ext2 comparison would tell you how much pramfs sucks (or not).
>
> Here the test with ext2 (same environment):
>
> Version 1.03e ------Sequential Output------ --Sequential Input- --Random-
> -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
> Machine Size:chnk K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
> hostname 15M:1k 10262 83 40847 82 38574 82 9866 92 62252 98 25204 81
> ------Sequential Create------ --------Random Create--------
> -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
> 1 19859 98 44804 61 68830 100 13566 99 157129 100 30431 98
>

Ok, so pramfs is significantly faster than ext2. Interesting, and good
for pramfs.
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html