[vdr] Re: Disk performance (was: vdr - some general questions)

[Andreas Roedl <flood@flood-net.de>]

Hello!

Am Freitag, 26. April 2002 11:47 schrieb Tobias Meyer-Janson:
> > My System:
> > Duron 1GHz/256MB/80GB, [...]
> > Suse 7.3 Pro, only reiser FS, [...]
> > Elitegroup K7S5A Mainboard with on board
> >     "Dual PCI IDE interfaces - support four IDE devices
> >     (PIO mode 4, DMA Mode 2, Ultra DMA 33/66/100)"
> > 1st Controller: HD, 2nd: DVD-ROM,
> > [...]
> > I asked hdparm:
> >     I/O support =  0 (default 16-bit)
> >     using_dma   =  1 (on)
>
> The HD is a Maxtor 4D080H4 80 GB IDE. I know it's not the fastest but I
> thought some DVB-Streams would be no problem for any modern HD.
> How can I check if the HD is the problem? As I mentioned earlier I have
> also often digital artefacts both in picture and sound.
>
> Is it enough to switch DMA on (hdparm says it *is* on) or should I use a
> special DMA-Mode? I know different HDs and controller have different DMA
> features - is this configured automatically? I think default should be
> the fastest possible.

I would _measure_ the disk performance with bonnie or bonnie++

  http://www.coker.com.au/bonnie++/

liquid:/video # bonnie++ -u 500:100 -s 250
Version  1.01    ------Sequential Output------ --Sequential Input- --Random-
                 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine     Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
liquid      250M  8177  76 22123  34 11755  12  8923  85 26080  15 149.3   0
                 ------Sequential Create------ --------Random Create--------
                 -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
           files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
              16  7540  86 +++++ +++  8431  89  7414  83 +++++ +++  7092  90

As you can see my system writes 22 MB and reads 26 MB per second. Bonnie++ is 
also able to test operations involving thousands of files in a directory. 
This is useful for people complaining that the "recordings menu" is to slow.


Andi

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