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

[Mike Marty <mikem@xxxxxxxxxxx>]

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
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