freebsd vs linux: performance problem

Shantanu Ghosh shantanu_ghosh at
Thu Dec 13 04:34:33 PST 2007


I am running FreeBSD 7.0 Beta1 and Linux FC6 on two identical pieces of
hardware - Dell poweredge with intel core2 duo. Each system has 4 CPUs.

Now, in simple memory access operations, I see the freebsd system being
noticably slower than the linux system. A simple C program that copies
from one memory buffer to another, when executed in a loop executes
between 10-30% slower on freebsd, as compared to linux. The assembly
code of the program used for testing is identical in both the cases.

One observation is that freebsd system performance decreases as the
size of the buffer increases. If the buffer is under 1k, both the
sytems give the same performance. freebsd performance is about 10%
slower if the buffer size is around 4k, and about 30% slower if the
buffer is around 1Mb. A benchmark like sysbench memory read operation
performs miserably on the freebsd system, compared to linux.

As far as I can see, the BIOS settings are identical on both the
machines. Any idea what could be going on?

Thanks and regards.

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