Re: Can PARI code be forced to run in 32MB L3 cache, mostly without RAM?

[hermann@stamm-wilbrandt.de]

I read that perf 
"l2_cache_accesses_from_dc_misses,all_data_cache_accesses" can help to 
get understanding of L1 cache misses, and all(?) cache use?

So does below execution with PARI code say, that 3,372,491,167 times 
cache was accessed, and 37,845,884 times L1 had a cache miss?
How t measure L2 misses and L3 cache misses?

How to see how much RAM access was done?

What about parisize and pasisizemax settings for making PARI code run 
inside cache?


hermann@7600x:~/RSA_numbers_factored/c++$ 
LD_LIBRARY_PATH=/home/hermann/Downloads/pari-2.15.3/GPDIR/lib \
> perf stat -e 
> l2_cache_accesses_from_dc_misses,all_data_cache_accesses,cycles,task-clock 
> \
> ./sqrtm1.smallest_known_1million_digit_prime
a = y^(-1) (mod p) [powm]; a *= x; a %= p
0.195755s
[M,V] = halfgcdii(sqrtm1, p)
0.217144s
[x,y] = [V[2], M[2,1]]
1e-06s
done

 Performance counter stats for 
'./sqrtm1.smallest_known_1million_digit_prime':

        37,845,884      l2_cache_accesses_from_dc_misses #   79.826 
M/sec
     3,372,491,167      all_data_cache_accesses   #    7.113 G/sec
     2,572,672,013      cycles                    #    5.426 GHz
            474.10 msec task-clock                #    0.999 CPUs 
utilized

       0.474457023 seconds time elapsed

       0.466410000 seconds user
       0.008041000 seconds sys


hermann@7600x:~/RSA_numbers_factored/c++$


Regards,

Hermann.

On 2023-06-29 19:58, hermann@stamm-wilbrandt.de wrote:
> There are 31 hits for "cache", but none helped me to answer subject 
> question:
> https://pari.math.u-bordeaux.fr/pub/pari/manuals/2.15.1/libpari.pdf
>
> If it is possible to restrict most part of computations to L3 cache,
> does one need to restrict parisize and parisizemax to that value as
> well?
> Or lower?
>
> My 7600X CPU has these caches:
> https://github.com/Hermann-SW/7600X#details-of-pc
> L1 Cache  384KB
> L2 Cache  6MB
> L3 Cache  32MB
>
> Under Linux, how can I tell whether program runs mostly from cache and
> not from RAM?
>
>
> My only C++ PARI code sofar:
> https://github.com/Hermann-SW/RSA_numbers_factored/blob/main/c%2B%2B/sqrtm1.smallest_known_1million_digit_prime.cc#L68-L93
>
> I could reduce input prime size down from 1million digits for testing
> to fit into L3 cache.
>
>
> Regards,
>
> Hermann.