Juan Casero wrote:
Can you elaborate on the reasons the opteron is better than the Xeon when it comes to disk io? I have a PostgreSQL 7.4.8 box running a DSS. One of our
Opterons have 64-bit IOMMU -- Xeons don't. That means in 64-bit mode, transfers to > 4GB, the OS must allocated the memory < 4GB, DMA to that block and then the CPU must do extra work in copying the memory to > 4GB. Versus on the Opteron, it's done by the IO adaptor using DMA in the background.
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