[mythtv] perf survey

Isaac Richards mythtv-dev@snowman.net
Thu, 19 Sep 2002 01:11:23 -0400


On Wednesday 18 September 2002 04:52 pm, Grant Taylor wrote:
> OK, I want to get to the bottom of my performance issues.  (I get
> unpleasant jitter with any codec at any resolution higher than
> 352x480).
>
> To that end, if you have a jitter/hang/stutter-free life *while
> recording one thing and watching another* on an Athlon XP 1800 with
> bt878 and gforce4 chips, at 480x480 or larger with any codec, I'm
> interested in learning:
>
>  - What codec are you using?

Tested recording at 640x480 with mpeg4 with a bitrate of 2600.  Playback is a 
480x480 rtjpeg file..  Average jitter is 5ms -- basically unnoticeable.  CPU 
usage is 65%.

>  - Are you using the nvidia binary driver?

Yes, version 29.60 (haven't recompiled a kernel since 31.23 came out).
AGP 4x, Fast Writes, and SBA enabled.  Using the nvidia AGP driver, and not 
the kernel driver.

>  - Is your mysql colocated on the server with mythtv?

yes.

>  - What is your disk speed?  7200?  5400?  Other?

7200

http://www.maxtor.com/en/support/products/desktop/performance_drives/diamondmax_plus_d740x_ultra_ata_133/index.htm
is the drive (sorry for the long url)

Running it off of the ata-100 controller, have the ata-133 controller turned 
off (takes _forever_ to scan on boot).

>  - What is your disk buffer size?  2MB?  Other?
>    [ cat /proc/ide/hda/cache ]

2 MB.

>  - What are your dma, multcount, and prefetch settings?
>    [ hdparm /dev/hda ]

 multcount    = 16 (on)
 using_dma    =  1 (on)
 readahead    =  8 (on)

>  - What are your "elevator" settings? [ elvtune /dev/hda1 ]

        read_latency:           2048
        write_latency:          8192
        max_bomb_segments:      0

>  - What is your CPU and bus speed? [ cat /proc/cpuinfo ]

cpu MHz         : 1536.833
bus speed is 133, o'course

>  - What is your memory type, speed, configuration, and size?

2 256MB PC2100 DIMMS.  Running at CAS2, aggressive timings.  The motherboard 
does use a hypertransport link to RAM, 

>  - What is your motherboard chipset? [ a function of `cat /proc/pci` ]

NVidia 415-D

>  - What is your kernel version? [ uname -a ]

Linux Alioth 2.4.20-pre2-ac3 #1 Thu Aug 15 17:20:36 EDT 2002 i686

>  - What is your compiler version? [ gcc -v ]

Reading specs from /usr/lib/gcc-lib/i386-linux/2.95.4/specs
gcc version 2.95.4 20011002 (Debian prerelease)

Something you didn't ask:

hdparm -tT /dev/hda/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.36 seconds =355.56 MB/sec
 Timing buffered disk reads:  64 MB in  1.59 seconds = 40.25 MB/sec

Isaac