Re: [Gems-users] Problems configuring direct cache in Ruby...

[David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>]

By the way, is it normal that m_assoc keeps changing between 1 and 2 all the time when running simulations with L2_CACHE_ASSOC = 2 ??

I guess it is normal, but I tell you just in case it could help determine the source of my problem.

Regards,
David

2009/6/27 David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>

Hi Dan.

I have tried what you said, and now my LRUPolicy.h's getVictim() function is this:

inline
Index LRUPolicy::getVictim(Index set) const {
  Time time, smallest_time;
  Index smallest_index;

  smallest_index = 0;
  smallest_time = m_last_ref_ptr[set][0];

  for (unsigned int i=0; i < m_assoc; i++) {
    time = m_last_ref_ptr[set][i];

    if (time < smallest_time){
      smallest_index = i;
      smallest_time = time;
    }
  }

  printf("m_assoc: %d\n", m_assoc);

  if (m_assoc==1) return 0;
  else return smallest_index;
}

When I run the simulation (using MSI_MOSI_CMP_directory protocol) for 1M instructions it prints "m_assoc: 1" several times, but when it reaches 7139 instructions executed, it exits with no errors or warnings, just like it did before changing getVictim() function.

I have also tried with another protocol (MOESI_CMP_directory) and in this case it seems to work fine, simulating 1M instructions.

So, what might then be the problem??

Thank you!!

Regards,
David

2009/6/25 David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>

Does anyone have any idea of what might be wrong with this ??

Thanks!!

2009/6/11 David Bonavila <david.bonavila@xxxxxxxxxxxxxxxxxx>

Hi,

I'm trying to configure a direct cache (associativity = 1) in Ruby, but I get an strange behavior.

This is my script:

read-configuration final-2p.check
magic-break-enable

@conf.con0.input = "cd /parsec/\n";
@conf.con0.input = "./bin/parsecmgmt -a run -i simsmall -x gcc-hooks -p bodytrack -n 2\n";

c

cpu-switch-time 1
instruction-fetch-mode instruction-fetch-trace
istc-disable
dstc-disable

load-module ruby
ruby0.setparam g_PROCS_PER_CHIP 2
ruby0.setparam g_NUM_PROCESSORS 2
ruby0.setparam NUMBER_OF_VIRTUAL_NETWORKS 5

ruby0.setparam_str g_REPLACEMENT_POLICY LRU
ruby0.setparam L1_CACHE_ASSOC 1
ruby0.setparam L1_CACHE_NUM_SETS_BITS 8
ruby0.setparam L2_CACHE_ASSOC 1
ruby0.setparam L2_CACHE_NUM_SETS_BITS 12

ruby0.init

load-module opal
opal0.init
opal0.sim-start "output_OBJ1-1_BODYTRACK_256KB_ASSOC1.opal"
opal0.sim-step 100000
opal0.stats

ruby0.dump-stats output_OBJ1-1_BODYTRACK_256KB_ASSOC1.ruby
q

I read in this mailing list that to configure a direct mapped cache I should set g_REPLACEMENT_POLICY to LRU. I did so, but when I run the script it simulates just 6.000 or 7.000 instructions and the simulation stops. No errors or warnings, all seems correct, but when I look at the stats file just 6 or 7 thousand instructions have been simulated.

If I change "L2_CACHE_ASSOC 1" to "L2_CACHE_ASSOC 2" everything works fine, and I have correctly simulated 20 million instruction with this configuration, even with "L1_CACHE_ASSOC" set to 1. So it's a problem with "L2_CACHE_ASSOC" param which is causing me trouble.

How should I configure a direct L2 cache??

Thank you all!!