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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