Messages in this thread | | | Date | Tue, 04 Oct 2011 15:45:21 -0400 | From | starlight@binnacle ... | Subject | Re: big picture UDP/IP performance question re 2.6.18 -> 2.6.32 |
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At 12:38 PM 10/4/2011 -0700, Joe Perches wrote: >On Tue, 2011-10-04 at 14:16 -0500, Christoph Lameter wrote: >> On Mon, 3 Oct 2011, starlight@binnacle.cx wrote: >> > I've come to the conclusion that Eric is right >> > and the primary issue is an increase in the >> > cost of scheduler context switches. Have >> > been watching this number and it has held >> > pretty close to 200k/sec under all scenarios >> > and kernel versions, so it has to be >> > a longer code-path, bigger cache pressure >> > or both in the scheduler. Sadly this makes >> > newer kernels a no-go for us. >> We had similar experiences. Basically latency >> constantly gets screwed up by the new fancy >> features being added to the scheduler and network >> subsystem (most notorious is the new "fair" >> scheduler, 2.6.23 made a big >> step down). > >Idly curious, have you compared bfs performance? >http://ck.kolivas.org/patches/bfs/bfs-faq.txt
No but it certainly does look very interesting.
Looks like trying it out not much more work than patching and building a kernel and running the benchmark. Will take a look and report back if I do. Little busy at present but should have time in a week or so.
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