Messages in this thread | | | Date | Wed, 23 Dec 1998 11:16:12 +0100 | From | Thomas Kunert <> | Subject | Re: Wanted: Secure-delete utility for Linux |
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Michael Shields wrote: > > In article <199812230309.AAA05174@sleipnir.valparaiso.cl>, > Horst von Brand <vonbrand@sleipnir.valparaiso.cl> wrote: > > There are faster methods, but I'd guess that the I/O time swamps everything > > else. > > Don't guess; measure. > > $ time ./a.out | dd bs=1048576 count=10000 of=/dev/null > 0+10000 records in > 0+10000 records out > Broken pipe > > real 0m4.010s > user 0m3.560s > sys 0m0.240s > > Your program generates roughly 2.5 GB/s on an unloaded Celeron 333. > (gcc 2.7.2.3, -O2) This exceeds the RAM bandwidth. >
Don't messure; guess :)
The results can't be worse.
2.5 GB/s, that is 8 Bytes/clockcycle or 2 loops/clockcycle, each loop consisting of calculation and fwrite-syscall. Processors can do a _lot_ in one clockcycle nowadays:)
Thomas
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