Hear us Roar
Article:
 |
|
Memory Contention in J2EE Applications for Multiprocessor Platforms
|
| Subject: |
|
Too simplistic |
| Date: |
|
2004-11-11 01:52:43 |
| From: |
|
jonathanrowe
|
|
|
|
Sorry, but this benchmark is way too simplistic:
1) On a 32bit windows box, 3gb to 4gb are always reserved for memory mapping. Therefore, a windows box with 3gb and one with 4gb will both still have only 3gb available to the OS. I believe this limitation is imposed by the BIOS.
2) The Xeon MP does not scale very well running most types of application, even the latest XeonMP's have a shared 400mhz FSB (3.2gb/s of bandwidth) - Intel have tried to improve scalability by increasing the L3 cache size, the latest Xeon Mp's have upto 4mb of cache. The Xeon 800 has an FSB of 133mhz (1.06gb/s), sharing this bus between 8 processors is like trying to suck a bucket of water through a straw! (scuse the analogy). Remember also that all I/O goes through the FSB, a 15k SCSI drive or a single gigabit ethernet LAN is capable of bursting at 80mb/s (8% of your FSB bandwidth!).
3) Also windows does not scale well at this level, try running this on an OS that really scales (solaris, some linux, AIX etc).
|
|
| |
