I have a core 2 duo, 32k L1 on each, 3 MB L2, from the sage install
this agrees:
sage-4.2: grep "cache size" install.log
checking the L1 cache size... 32768 Bytes
checking the L2 cache size... 3145728 Bytes
and:
./cache
8 0.017 1.877
16 0.024 1.353
32 0.045 1.911
64 0.106 2.357
128 0.372 3.513
256 0.879 2.361
512 1.882 2.141
1024 3.877 2.060
2048 8.277 2.135
4096 21.497 2.597
8192 134.200 6.243
16384 372.665 2.777
32768 850.994 2.284
65536 1799.467 2.115
64 4096
-Marshall
On Oct 28, 6:40 am, Gonzalo Tornaria <torna...@math.utexas.edu> wrote:
> Laptop:
>
> Intel(R) Core(TM)2 CPU T5300 @ 1.73GHz
> 8 0.023 7.611
> 16 0.046 2.018
> 32 0.093 2.034
> 64 0.289 3.097
> 128 0.641 2.216
> 256 0.744 1.160
> 512 1.542 2.073
> 1024 3.394 2.202
> 2048 7.826 2.305
> 4096 52.330 6.687
> 8192 146.481 2.799
> 16384 314.824 2.149
> 32768 662.751 2.105
> 65536 1331.857 2.010
> 32 2048
>
> This is correct.
>
> Server:
> Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz
> 8 0.014 7.452
> 16 0.027 2.014
> 32 0.055 1.999
> 64 0.175 3.188
> 128 0.400 2.282
> 256 0.446 1.116
> 512 0.919 2.060
> 1024 1.867 2.030
> 2048 3.779 2.024
> 4096 8.177 2.164
> 8192 25.677 3.140
> 16384 164.208 6.395
> 32768 383.568 2.336
> 65536 802.709 2.093
> 32 8192
>
> Not quite; this core 2 quad has two 6M L2 caches (one for each pair of
> cores) for a total 12M of L2 (no shared L3). The L1 is correct.
>
> Gonzalo
>
> On Tue, Oct 27, 2009 at 6:51 PM, Martin Albrecht
>
> <m...@informatik.uni-bremen.de> wrote:
>
> > Hi there,
>
> > in the thread
>
> > http://is.gd/4EMT8
>
> > David and I agreed that M4RI should have a better, more robust and cross-
> > platform mechanism to check for cache sizes.
>
> > Thus I wrote a little C program to check for the cache size using timings of
> > random-ish memory access.
>
> > The program is available at:
>
> > http://sage.math.washington.edu/home/malb/cache.c
>
> > On my Core 2 Duo and on my Opteron (both running Linux 64-bit) it does
> > report
> > correct sizes. So far so good. On sage.math it reports L3 cache size instead
> > of L2 but I guess that this is probably what we want anyway (well, L2 is 3MB
> > which I don't check explicitly since I only check powers of two)
>
> > I'd appreciate if those people on this list who have different hardware or
> > software (OSX, Solaris, PPC, Sparc) could compile the program and report
> > back
> > whether the program reports correct sizes for them. To compile and run:
>
> > gcc -std=c99 -O3 cache.c -o cache
> > ./cache
>
> > Cheers,
> > Martin
>
> > --
> > name: Martin Albrecht
> > _pgp:http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99
> > _otr: 47F43D1A 5D68C36F 468BAEBA 640E8856 D7951CCF
> > _www:http://www.informatik.uni-bremen.de/~malb
> > _jab: martinralbre...@jabber.ccc.de
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