CSC 456 Fall 2013/1c wa
Trends in cache size and organization
Task 1c. Trends in cache size and organization Over the years, caches have grown larger--up to a point, and then L1 caches tended for awhile to decrease in size. Why? In the early 1980s, associativity increased; beginning about 1990, it decreased, and then by about 2000, it was increasing again. Why? When was the first machine with an L2 cache? An L3 cache? How fast were the various levels of caches, and how did this speed compare to main memory? There is a wealth of information to bring to bear on this topic.
Theory: Cache Associativity decreased as cache size became larger because it became too expensive to have to search the cache each time once the cache was too large. Also, bigger the cache size as a percentage of main memory, the less need for associativity. But while caches and main memory have both grown, main memory size has grown faster in the 2000’s. So when the percentage of cache to main memory goes down associativity needs to increase.
The Pentium/Pentium (1995) Pro was the first processor to have the l2 cache on the processor chip. Before this, the l2 cache was an option to add on to the motherboard. [1]
Systems to consider in table
Pentium
amd
Mips
sun-microsystems: sparc
ibm: power pc
DEC: alpha
Penalty <100 when before 2000
after 2000 started to increase to get to main memory
< 20 1 level fine
<=100 2 level
>=200 3 level
miss rate reported, spec benchmarks
>=200 3 level
miss rate reported, spec benchmarks
L1, L2, L3 Size and Associativity
| System | Year | L1 Size | L1 Speed (cc) | L1 Associativity | L2 Size | L2 Speed | L2 Associativity | L2 On-Chip | L3 Size | L3 Speed | L3 Associativity | L3 On-Chip | Main Mem Penalty (cc) | Notes: | |
| IBM 360/85 | 1968 | 16 - 32 KB | ? | Sector | None | N/A | N/A | N/A | None | N/A | N/A | N/A | ? | First processor with a cache, clock speed 12.5MHz | |
| IBM 486 | 1989 | 8 kb | ? | L1 Associativity | 256 kb | no | |||||||||
| Intel 80486 | 1989 | 8 KB | ? | 4-way associative | None | N/A | N/A | N/A | None | N/A | N/A | N/A | ? | First processor with a cache, clock speed 12.5MHz | |
| SuperSPARC | ?/1992 | (16+20) KB | ? | 4 & 5 way set | 0 - 2 MB | ? | ? | No | N/A | ? | Used to render Toy Story, Core @ 40MHz | ||||
| Alpha 21064(DEC) | 09/1992 | (8+8) KB | 1 | Direct | 128kb - 16mb | 3-16 cc | Direct | No | N/A | 8 cc | |||||
| UltraSPARC | 06/1995 | (16+16) KB | 1 | 2-Way & Direct | 512KB - 4MB | 1, pipe=3 | Direct | No | N/A | 2-3 | 64-bit w/ Core@200MHz | ||||
| Alpha 21164(DEC) | 01/1995 | (8+8) KB | 1 | Direct | 96 Kb | 2 | 3 way set | Yes | ? | ||||||
| K6-III | 1999 | 32 kib | 100 mhz | 2 way | 256 kib | 100 mhz | 4 way | yes | 1 mb | no | |||||
| Pentium 4 | 10/2000 | 8 KB (trace) | 2 | 4 Way | 256KB | full speed | 8 Way | Yes | None | 4 (Mem controller) | |||||
| UltraSPARC III | ?/2001 | (32+64) KB | 1 | 4 Way | 2-8MB | 2-3 | ? | No | 4 (Mem controller) | ||||||
| Itanium 2 | 2002 | 16 KB | 1 | 4 -way | 256KB | 5 | 8-way | yes | 3 MB | 12 | 12 way (4 per MB) | Yes | ? |
L1, L2, L3 Size Evolution
| Processor | System Type | Year | L1 size | L2 size | L3 size |
| IBM 360/85 | Mainframe | 1968 | 16 to 32 KB | — | — |
| PDP-11/70 | Minicomputer | 1975 | 1 KB | — | — |
| VAX 11/780 | Minicomputer | 1978 | 16 KB | — | — |
| IBM 3033 | Mainframe | 1978 | 64 KB | — | — |
| IBM 3090 | Mainframe | 1985 | 128 to 256 KB | — | — |
| Intel 80486 | PC | 1989 | 8 KB | — | — |
| Pentium | PC | 1993 | 8 KB/8 KB | 256 to 512 KB | — |
| PowerPC 601 | PC | 1993 | 32 KB | — | — |
| PowerPC | 620 PC | 1996 | 32 KB/32 KB | — | — |
| PowerPC G4 | PC/server | 1999 | 32 KB/32 KB | 256 KB to 1 MB | 2 MB |
| IBM S/390 G4 | Mainframe | 1997 | 32 KB | 256 KB | 2 MB |
| IBM S/390 G6 | Mainframe | 1999 | 256 KB | 8 MB | — |
| Pentium 4 | PC/server | 2000 | 8 KB/8 KB | 256 KB | — |
| IBM SP | High-end server | 2000 | 64 KB/32 KB | 8 MB | — |
| CRAY MTAb | Supercomputer | 2000 | 8 KB | 2 MB | — |
| Itanium | PC/server | 2001 | 16 KB/16 KB | 96 KB | 4 MB |
| SGI Origin 2001 | High-end server | 2001 | 32 KB/32 KB | 4 MB | — |
| Itanium 2 | PC/server | 2002 | 32 KB | 256 KB | 6 MB |
| IBM POWER5 | High-end server | 2003 | 64 KB | 1.9 MB | 36 MB |
| CRAY XD-1 | Supercomputer | 2004 | 64 KB/64 KB | 1MB | — |
DRAM Memory Standards:
| Standard | Mem Clock | Cycle time | I/O Bus Clock | Module Name | Peak Transfer Rate | Prefetch | Latency | Year |
| DDR2-400 | 100MHz | 10 ns | 200 MHz | PC2-3200 | 3200 MB/s | 4 n | 4-6 Bus CC | 2003 |
| DDR2-533 | 133 MHz | 7.5 ns | 266 | PC2-4200 | 4266 MB/s | 4 n | ||
| DDR2-667 | 166 MHz | 6 ns | 333 MHz | PC2-5300 | 5333 MB/s | 4 n | ||
| DDR2-800 | 200 MHz | 5 ns | 400 MHz | PC2-6400 | 6400 MB/s | 4 n | ||
| DDR2-1066 | 266 MHz | 3.75 ns | 533 MHz | PC2-8500 | 8533 MB/s | 4 n | ||
| DDR3-800 | 100 MHz | 10 ns | 400 MHz | PC2-6400 | 6400 MB/s | 8 n | 5-9 ns (7 avg.) | 2007 |
| DDR3-1066 | 133 MHz | 7.5 ns | 533 MHz | PC2-8500 | 8533 MB/s | 8 n | ||
| DDR3-1333 | 166 MHz | 6 ns | 667 MHz | PC2-10600 | 10667 MB/s | 8 n | ||
| DDR3-1600 | 200 MHz | 5 ns | 800 MHz | PC2-12800 | 12800 MB/s | 8 n |
References
Itanium Specs(p.20)
Pentium Pro
Intel Processors
First on-board L1
Cache Trend Table
Sector Caches
DDR2/3 Speeds
Memory Wall