What is cache?
Cache
memory is a small block of very high-speed RAM where recently read
blocks of memory are stored. Conceptually, the idea is to try to guess
what chunk the currently running program will next request and provide
that chunk as quickly as possible. Recently-accessed memory chunks is
placed in fast memory residing as close as possible to the processor,
reducing costly runs out to slow main memory.
L1 cache is the smaller, faster,
more expensive cache (typical size is about 16 - 32k, operating at
processor speed) located onboard the processor. This on-chip location
gives an immediate speed advantage to L1 since it can talk directly to
the processor without having to send signals across the bus lines. Due
to the location of L1 cache, it is often referred to as "internal
cache", while L2 is often referred to as "external cache" (since it is
generally located off-chip and must communicate with the CPU through bus
lines). L2 cache is typically constructed using SRAM (Static Random
Access Memory) modules.
With the use of the tool called Cachchk
you can easily check your system’s L1 and L2 cache memory for size and
speed. The tool performs memory access timing tests, to see if you have a
cache, how many caches, and to check the access speed. Cachchk will
also perform memory accesses to verify the L1 and L2 cache usage, it
will report the speeds and sizes of each cache, and it will verify if
all of your memory is, or is not cached.
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