[Beowulf] Enabling I/OAT and DCA on a live system
linus at ussarna.se
Tue Jul 7 03:46:45 PDT 2009
Hi All, though this might be of interest to someone on the list. It is
an article about how to enable I/OAT and DCA on a live system or a
system that hides the option in the BIOS.
According to the post:
"So by using I/OAT the network stack in the Linux kernel can offload
copy operations to increase throughput. I/OAT also includes a feature
called Direct Cache Access (DCA) which can deliver data directly into
processor caches. This is particularly cool because when a network
interrupt arrives and data is copied to system memory, the CPU which
will access this data will not cause a cache-miss on the CPU because DCA
has already put the data it needs in the cache. Sick.
Measurements from the Linux Foundation project indicate a 10% reduction
in CPU usage, while the Myri-10G NIC website claims they’ve measured a
40% reduction in CPU usage. For more information describing the
performance benefits of DCA see this incredibly detailed paper: Direct
Cache Access for High Bandwidth Network I/O."
Regards /Mostly Lurking
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