C > determine cache size

[CH]

determine cache size

hello,

can anyone help me out in writing a C program to determine the size of L1 and L2 cache. I'd also like to be able to determine whether the L1 cache is 1-way, 2-way or 4-way.

What I've done up to now was create a large array, stride through the array many number of times, reading and writing to each location while timing it. Then I would the the exact same thing again without the reading and writing to memory... then use the difference between two results as a way of determining the sizes.

The method I'm using is very inaccurate, and I'm a litle confused on how the whole process of caching occurs ( e.g. the way cache pulls in only 32B lines at a time )

any advice will be much appreciated, thx.

 

[tom324]

linux determine cache size

It is not part of C language. What you are looking for is some dirty low level function. Which RTOS or OS are you using?

Tom

 

[CH]

linux get dcache icache size

I'll be using w2k and rh linux.

I've found two pieces of C code that do some of what I want, but the first piece is too complex for me to understand correctly. The second is simpler but it breaks into macros written in asm (which i dont understand) to count the number of clock ticks that have passed for a number of read/writes to cache.

 

[tom324]

determining cache size linux

I do not know for w2k, but for RedHat /proc/cpuinfo is a way to go. Do not reinvent the wheel - just use info from /proc file system.

BTW, enter "linux L1 cache size" as keywords in google.

Tom

 

[CH]

how to calculate cache size using a c program

thx tom. for anyone else interesed in this, look here for a quick tutorial on how to go about coding the solution to this problem.