Simple BDE disc encryption benchmark
Daniel Eriksson
daniel_k_eriksson at telia.com
Fri Aug 6 04:35:37 PDT 2004
Hi! I just ran a very simple benchmark on the GBDE disc encryption in
CURRENT. The benchmark setup looked like this:
* Slow machine (Celeron 366, 128MB mem)
* 5-CURRENT from yesterday, running off of some old ATA disc
* 2 x 9GB 10k rpm SCSI discs hooked up to an Adaptec 2940
The benchmark was to copy the /usr directory (copied from the ATA disc,
1.7GB) or a directory containing big files (/bigfiles, 1.7GB in 16 files
created by 'dd if=/dev/random ...') from scsi disc 1 to scsi disc 2. I ran
each benchmark twice and took a simple average of the results.
unencrypted to unencrypted:
/usr : 697 real 10.6 user 235 sys (~50% idle)
/bigfiles: 123 real 0.4 user 84 sys (~25% idle)
unencrypted to encrypted:
/usr : 1778 real 10.7 user 236 sys (~35% idle)
/bigfiles: 379 real 0.4 user 82 sys (~10% idle)
encrypted to encrypted:
/usr : 1978 real 11.6 user 242 sys (~25% idle)
/bigfiles: 615 real 0.4 user 80 sys (0% idle)
The only time the CPU was completely busy was when copying /bigfiles from
encrypted to encrypted.
My question is: Why does the it take so much longer when encryption is
involved even though 'top' seems to think there are CPU cycles left to burn?
/Daniel Eriksson
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