freebsd vs linux: performance problem

Kip Macy kip.macy at
Thu Dec 13 20:07:04 PST 2007

On Dec 13, 2007 4:07 AM, Shantanu Ghosh <shantanu_ghosh at> wrote:
> Hi,
> 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?

Are you running with ULE or 4BSD? Have you checked that the BIOS cache
settings are identical?


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