The merging of anon_vma and 4G/4G
Posted May 27, 2004 15:08 UTC (Thu) by seanegan
Parent article: The merging of anon_vma and 4G/4G
and there is fear of the (possibly overstated) performance overhead that the 4G/4G mode imposes.
Where I work we have tested the 4G/4G patch in a 2.4 kernel. Our app is a network server running in an poll() based event loop; it needs a large datastructure in memory and is receiving and sending small message requests about that large data set. Bottom line, our app is VERY syscall dominated. To get more user space memory we looked into the 4G/4G patch.
The performance impact was enormous, 30-50% loss of requests per second. Swapping memory spaces for every syscall killed our app so much that it didn't even need the greater memory space.
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