Re: Is there a way to obtain a machine's cache line size?

[seebs%seebs.net@localhost (Peter Seebach)]

In message <145C3AC8-317E-4D8B-B696-19824A6B81AE%dell.com@localhost>, Paul 
Koning writes:
>On Jan 20, 2011, at 2:47 PM, der Mouse wrote:
>>> I see there is a compile time constant CACHE_LINE_SIZE in
>>> <sys/param.h> which currently seems to be always be set to 64, but
>>> I'm pretty certain that is not necessarily a correct value.

>> You are correct; to cite the one example I currently have swapped into
>> my brain, the Super-H used in the Dreamcast has 32-byte cache lines
>> (true of the I-cache and D-cache both).

>I'm curious why non-kernel components would care.

Look at the output of lmbench.  Empirically, there are real-world performance
effects in some boundary cases.

Some people care about performance enough to tune for stuff like this.

-s