[Xen-users] IDE Disc Performance problems with Xen3-unstable

[Michael Lang <michi+xen@xxxxxxxxxxxxxxxxxxxx>]

Hi everyone,

ive encountered performance problems with Xen3-unstable and a raid5 with 5 120Gb
 Maxtor IDE discs (1 Spare). After testing in different Kernels i also noticed
that 'normal' IDE Disc access is very slow

using Whitebox Linux 4 (eq RHEL 4) the performance seems to be okay for this IDE
Raid, but using Xen3-unstable Domain-0 the Performance is incredible slow ...

does anyone know why ?
here are the bonnie results, using the configuration
1 IDE Disc + LVM (physical Disc benchmark)
4 IDE Discs Raid5 + LVM (raid5)

thanks for any hint
Kind regards
Michael Lang

Whitebox 4 original Kernel
# bonnie -d tmp/ -s 100 -v 5 -p 2
Bonnie: Warning: You have 1011MB RAM, but you test with only 100MB datasize!
Bonnie:          This might yield unrealistically good results,
Bonnie:          for reading and seeking and writing.
Bonnie 1.4: File 'tmp//Bonnie.3645', size: 104857600, volumes: 5
Writing with putc()...         done:  17308 kB/s  77.2 %CPU
Rewriting...                   done:  64234 kB/s  41.6 %CPU
Writing intelligently...       done:  53365 kB/s  30.4 %CPU
Reading with getc()...         done:  21202 kB/s  91.0 %CPU
Reading intelligently...       done: 369841 kB/s  99.9 %CPU
Seek numbers calculated on first volume only
Seeker 1...Seeker 2...start 'em...done...done...
              ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek-
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (02)-
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU   /sec %CPU
server 5* 100 17308 77.2 53365 30.4 64234 41.6 21202 91.0369841 99.9 32015.1
97.6

Whitebox 4 xen3-unstable Kernel physical Disc
# bonnie -d . -s 100 -v 5 -p 2
Bonnie: Warning: You have 500MB RAM, but you test with only 100MB datasize!
Bonnie:          This might yield unrealistically good results,
Bonnie:          for reading and seeking and writing.
Bonnie 1.4: File './Bonnie.5678', size: 104857600, volumes: 5
Writing with putc()...         done:   3431 kB/s  85.6 %CPU
Rewriting...                   done:   1898 kB/s  52.8 %CPU
Writing intelligently...       done:   4248 kB/s  67.7 %CPU
Reading with getc()...         done:   3414 kB/s  74.4 %CPU
Reading intelligently...       done:   5203 kB/s  69.1 %CPU
Seek numbers calculated on first volume only
Seeker 1...Seeker 2...start 'em...done...done...
              ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek-
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (02)-
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU   /sec %CPU
server 5* 100  3431 85.6  4248 67.7  1898 52.8  3414 74.4  5203 69.1  165.1  0.4


Whitebox 4 xen3-unstable Kernel raid5
# bonnie -d tmp/ -s 100 -v 5 -p 2
Bonnie: Warning: You have 500MB RAM, but you test with only 100MB datasize!
Bonnie:          This might yield unrealistically good results,
Bonnie:          for reading and seeking and writing.
Bonnie 1.4: File 'tmp//Bonnie.5605', size: 104857600, volumes: 5
Writing with putc()...         done:   6613 kB/s  44.2 %CPU
Rewriting...                   done:   4501 kB/s   7.5 %CPU
Writing intelligently...       done:   8698 kB/s  19.8 %CPU
Reading with getc()...         done:   7867 kB/s  46.6 %CPU
Reading intelligently...       done:  11836 kB/s   7.3 %CPU
Seek numbers calculated on first volume only
Seeker 1...Seeker 2...start 'em...done...done...
              ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek-
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (02)-
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU   /sec %CPU
server 5* 100  6613 44.2  8698 19.8  4501  7.5  7867 46.6 11836  7.3  269.9  2.0



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