[Gems-users] L2 cache banks question

[Filipe <scoton@xxxxxxxxx>]

Hi!

I have a question about banks with the MSI_MOSI_CMP_directory and the MOESI_CMP_directory...

I did some tests using 4, 8 and 16 banks with both protocols and an L2 cache with 16MB and 8MB...
The CMP has 32 cores accessing the L2...

For SPLASH2-OCEAN, I got similar results for each protocol... these are the execution times in cycles... 

MSI: 
110681587 - 16MB - 16 banks
110882613 - 16MB - 4 banks
110007560 - 16MB - 8 banks

112847680 - 8MB - 16 banks
115278293 - 8MB - 8 banks
114196480 - 8MB - 4 banks

MOESI:
91810800 - 16MB - 16 banks
90638080 - 16MB - 8 banks
91811853 - 16 MB - 4 banks

91366667 - 8 MB - 16 banks
90484880 - 8 MB - 8 banks
92219093 - 8 MB - 4 banks

the differences are less then 5% in each protocol... is that correct? why is it so small? 
is the number of banks too small for the number of cores? 

I would appreciate any kind of help to understand this.

Thank you  very much!


-- 
Filipe Montefusco Scoton