June 23, 2000:  News on Willamette cache organisation


An early memory benchmark (cachemem2.2) might reveal some of Willamette's internal cache organization:
 
 
L1 Data Cache:  8 kByte,    ( 4 way set-associative)
L2 Cache:  256 kByte
L1 / L2 relationship Inclusive and Write Thru.

The 8 kByte size for the L1 data cache follows from the decrease in read bandwidth at block sizes larger then 8kByte (We don't know actually how cachemem arrives at these numbers). The  4 way set-associativity was already disclosed by Intel. The 256 kByte is a known number from OEM presentatons.The benchmark shows an unexplained bandwidth decrease at the 128 kByte level. The L1 data cache is operating in a Write-Thru mode: All writes to the L1 data cache are also written to the L2 cache.  This means that the L2 cache is "Inclusive":  All L1 cache-lines are also found in the L2 cache.
 


Willamette meets Pikachu

The 800 MHz Willamette system seems to come from an early system integrator (Which should be possible considering the planed October launch)  It was exposed to the web by a young guy nicknamed "Pikachu"
Some of the more knowledgeable and well kown posters on the web contacted him via ICQ and obtained the following benchmark (cachemem2.2 by LRMS) which we may take seriously (in spite of the posters nickname "Idiot")
 

CPUID support detected... 'GenuineIntel' with FPU TSC MMX 
Family=15 Model=0 Step=1 Type=0 
Chipset (Vendor/Device ID(Rev)): Intel/2530(00) 
CPU clock: 3200.1 MHz  (edit: The BIOS mentions correctly 800MHz)
Using 32MB physical memory block 
Now testing memory bandwidth (please wait some seconds) 
Block of 1KB,       Speed R/W:  6446.0 / 2690.0 MB/s   ( 3 /  9 cycles) 
Block of 2KB,       Speed R/W:  6104.3 / 2611.6 MB/s   ( 3 /  9 cycles) 
Block of 4KB,       Speed R/W:  5846.2 / 2646.9 MB/s   ( 4 /  9 cycles)
Block of 8KB,       Speed R/W:  5786.0 / 2637.1 MB/s   ( 4 /  9 cycles)
Block of 16KB,      Speed R/W:  3185.1 / 2524.7 MB/s   ( 7 /  9 cycles)
Block of 32KB,      Speed R/W:  3147.9 / 2505.9 MB/s   ( 7 /  9 cycles)
Block of 64KB,      Speed R/W:  3180.5 / 2485.2 MB/s   ( 7 /  9 cycles) 
Block of 128KB,     Speed R/W:  3162.7 / 2635.1 MB/s   ( 7 /  9 cycles)
Block of 256KB,     Speed R/W:  1579.0 / 1258.5 MB/s   (15 / 19 cycles)
Block of 512KB,     Speed R/W:  1161.9 / 812.2  MB/s   (21 / 30 cycles) 
Block of 1024KB,    Speed R/W:  1164.3 / 828.1  MB/s   (20 / 29 cycles)
Block of 2048KB,    Speed R/W:  1169.0 / 848.6  MB/s   (20 / 28 cycles)
Block of 4096KB,    Speed R/W:  1085.3 / 723.0  MB/s   (22 / 33 cycles)
Block of 8192KB,    Speed R/W:   978.4 / 818.0  MB/s   (24 / 29 cycles)
Block of 16384KB,   Speed R/W:  1051.2 / 838.0  MB/s   (23 / 29 cycles)
Block of 32768KB,   Speed R/W:  1065.2 / 768.9  MB/s   (22 / 31 cycles)

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