Re: [Gems-users] How to identify cache hit rate in Ruby?

["Dave Z." <zhu_dave@xxxxxxxxx>]

If I put the following code in Sequencer::makeRequest,
and set REMOVE_SINGLE_CYCLE_DCACHE_FAST_PATH to true,
then I should get the same number of hits/misses in
both the Sequencer stats and cache controllers, right?

    if ((request.getType() == CacheRequestType_LD) ||
	(request.getType() == CacheRequestType_ST) ||
	(request.getType() == CacheRequestType_IFETCH)) {
      if (hit) numOfHits++;
      else numOfMisses++;
    }

But it doesn't give me the same numbers. Is there any
other parameter that I need to reconsider?

Thanks,

Dave


 
--- Mike Marty <mikem@xxxxxxxxxxx> wrote:

> With REMOVE_DCACHE_FAST_PATH (or whatever the name
> is) is set to 
> "false", the Ruby sequencer directly accesses the L1
> cache objects to 
> determine a hit.  If there is an L1 hit, then the L1
> cache controller is 
> not invoked and you will not see "Load, Ifetch, and
> Store" events.  If 
> you want to  see these events in the controllers,
> then set the above 
> flag to "true". 
> 
> --Mike
> 
> 
> 
> Lei Yang wrote:
> > But wait, when I compare the sum of L1D and L1I
> misses,  and the sum
> > of L1 Load, Ifetch, and Store, they are exactly
> the same, does this
> > mean that all L1 access are misses?
> >
> > Lei
> >
> > On 11/1/07, Lei Yang <lei.d.yang@xxxxxxxxx> wrote:
> >   
> >> Thanks Mike!
> >>
> >> In addition to the simics driver transaction
> results stats, could we
> >> also look at the chip stats? (Right below the
> transaction results
> >> stats, which I didn't notice before).
> >>
> >> Chip Stats
> >> ----------
> >>
> >>  --- L1Cache ---
> >>  - Event Counts -
> >> Load  4775
> >> Ifetch  10102
> >> Store  25032
> >>
> >> This way, we'll know both L1 and L2 miss rates.
> >>
> >> Maybe we should consider include the results of
> miss/hit rates in the
> >> L1/L2 stats in the next release.
> >>
> >> Lei
> >> On 11/1/07, Mike Marty <mikem@xxxxxxxxxxx> wrote:
> >>     
> >>> misses_per_transaction simply divides the total
> misses by the total
> >>> number of transactions.  This is not
> transactions in Transactional
> >>> Memory.  This is workload transactions (i.e., a
> transaction in the
> >>> Apache web server workload).
> >>>
> >>> You have the L1D and L1I misses.  To get the
> total accesses (assuming
> >>> REMOVE_FAST_PATH... is set to false), look for
> the following:
> >>>
> >>> Simics Driver Transaction Results Stats
> >>> ------------------------------------------
> >>> Fast path: 114008467
> >>> Request missed: 3926280
> >>>
> >>> The "Request missed" should equal the L1D and
> L1I misses.  The "Fast
> >>> path" indicates how many requests were made to
> the Ruby sequencer, but
> >>> hit in the L1 caches.
> >>>
> >>> --Mike
> >>>
> >>>
> >>>
> >>> Lei Yang wrote:
> >>>       
> >>>> Dear list,
> >>>>
> >>>> I'm wondering whether Ruby provides such
> statistics like cache
> >>>> hit/miss rate? For example, in the following
> stats report from Ruby:
> >>>>
> >>>> L1D_cache cache stats:
> >>>>   L1D_cache_total_misses: 29807
> >>>>   L1D_cache_total_demand_misses: 29807
> >>>>   L1D_cache_total_prefetches: 0
> >>>>   L1D_cache_total_sw_prefetches: 0
> >>>>   L1D_cache_total_hw_prefetches: 0
> >>>>   L1D_cache_misses_per_transaction: 29807
> >>>>   L1D_cache_misses_per_instruction: 0.000143247
> >>>>   L1D_cache_instructions_per_misses: 6980.94
> >>>>
> >>>>   L1D_cache_request_type_LD:   16.0197%
> >>>>   L1D_cache_request_type_ST:   82.7557%
> >>>>   L1D_cache_request_type_ATOMIC:   1.22454%
> >>>>
> >>>>   L1D_cache_access_mode_type_SupervisorMode:  
> 6933    23.2596%
> >>>>   L1D_cache_access_mode_type_UserMode:   22874 
>   76.7404%
> >>>>   L1D_cache_request_size: [binsize: log2 max:
> 64 count: 29807 average:
> >>>> 4.90469 | standard deviation: 4.44371 | 0 642
> 88 23854 5077 0 0 146 ]
> >>>>
> >>>> We know the total L1D cache misses, and the
> misses_per_instruction.
> >>>> But do we know the total number of cache
> acesses, and thus the
> >>>> hit/miss rate? Also, what does
> misses_per_transaction mean?
> >>>>
> >>>> Thank you in advance!
> >>>> Lei
> >>>> _______________________________________________
> >>>> Gems-users mailing list
> >>>> Gems-users@xxxxxxxxxxx
> >>>>
>
https://lists.cs.wisc.edu/mailman/listinfo/gems-users
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> list by adding
> "site:https://lists.cs.wisc.edu/archive/gems-users/";
> to your search.
> >>>>
> >>>>         
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