On Friday 28 October 2005 17:30, Marcelo Tosatti wrote: >[...] > David, > > Do you have CONFIG_PIN_TLB enabled? > > If you do, please patch this in: > > http://www.kernel.org/git/?p=linux/kernel/git/marcelo/8xx-fixes;a=commitdif >f;h=a41ba028534c45280170c05c23609ea84f34b38a > > And select DEBUG_PIN_TLBIE.
Ok, done that... no change. I don't get any of those debug messages, so I guess that was not the problem. I have made another test in the meantime, trying to check if cache is working. The test is pretty simple: see how fast I can fill a block of memory whose size is increasing by a power of two. You should expect to see a step-like decrease in speed when surpassing the size of the data cache (4kbyte). The results are very suspicious: kernel-2.4: Memsize 512 : 39.342773 Mbyte/s Memsize 1024 : 41.871094 Mbyte/s Memsize 2048 : 43.212891 Mbyte/s Memsize 4096 : 40.117188 Mbyte/s Memsize 8192 : 28.148438 Mbyte/s Memsize 16384 : 28.484375 Mbyte/s Memsize 32768 : 28.656250 Mbyte/s Memsize 65536 : 28.687500 Mbyte/s This looks quite healthy: above 4kbyte we see a clear drop in performance, so we just learned that our data-cache is most probably 4kbyte in size, wow! Kernel-2.6: Memsize 512 : 21.033691 Mbyte/s Memsize 1024 : 22.047852 Mbyte/s Memsize 2048 : 22.601562 Mbyte/s Memsize 4096 : 22.882812 Mbyte/s Memsize 8192 : 23.007812 Mbyte/s Memsize 16384 : 23.093750 Mbyte/s Memsize 32768 : 23.125000 Mbyte/s Memsize 65536 : 23.125000 Mbyte/s No, sir, no cache detected ! Where do I have to look now? Greetings, -- David Jander Protonic Holland.
