Re: [Gems-users] Finding the values of latency

[Rakesh Komuravelli <komurav1@xxxxxxxxxxxx>]

Hi Sparsh,

On Tue, Dec 1, 2009 at 4:17 PM, sparsh mittal ISU <sparsh@xxxxxxxxxxx> wrote:

Thanks a lot Philip and Rakesh for your answers, which are useful for me. I am using default configuration in gems 2.1 with MOSI_SMP_bcast. REMOVE_SINGLE_CYCLE_DCACHE_FAST_PATH is set to false. Is there any other default configuration file for this protocol?

 

All the default values are set in ruby/config directory. If you want to use a different value for any of the configuration parameters, use ruby0.setparam before running ruby0.init. This way you can avoid ruby compilation every time you modify a parameter.

Could you clarify, what does, memory latency refers to? Is it: MEM_CTL_LATENCY: 12 or MEMORY_RESPONSE_LATENCY_MINUS_2: 158  // determines memory response latency?

I think its MEMORY_RESPONSE_LATENCY_MINUS_2. If you look at MOSI_SMP_bcast-dir.sm, it uses MEMORY_LATENCY which is typedef'ed in config/RubyConfig.h

 

I assume that last one mentioned in the mail of Philip is L1 miss, L2 miss and memory access. And also the directory latency is DIRECTORY_LATENCY: 80, and not DIRECTORY_CACHE_LATENCY: 6.

I am assuming the same too. This is dependent on specific protocol implementation. The above list Phil mentioned is for MOESI_CMP_directory. Its different for MOSI_SMP_bcast that you have asked for. Please look at MOSI_SMP_bcast-mem.sm file. I don't think it uses any directory latencies.

I would be thankful for your comments.
Sparsh

Thanks,

Rakesh