On Tuesday 07 February 2006 17:15, Andrew Gallatin wrote: > John Baldwin writes: > > On Monday 06 February 2006 17:37, Andrew Gallatin wrote: > > > John Baldwin writes: > > > > On Monday 06 February 2006 14:46, Andrew Gallatin wrote: > > > > > Andre Oppermann writes: > > > > > > Andrew Gallatin wrote: > > > > > > > Why dooes machdep.cpu_idle_hlt=1 drop my 10GbE network rx > > > > > > > performance by a considerable amount (7.5Gbs -> 5.5Gbs)? > > > > > > > > You may be seeing problems because it might simply take a while for > > > > the CPU to wake up from HLT when an interrupt comes in. The 4BSD > > > > scheduler tries to do IPIs to wakeup any sleeping CPUs when it > > > > schedules a new thread, but that would add higher latency for > > > > ithreads than just preempting directly to the ithread. Oh, you > > > > have to turn that on, it's off by default > > > > (kern.sched.ipiwakeup.enabled=1). > > > > > > Hmm.. It seems to be on by default. Unfortunately, it does not seem > > > to help. > > > > I'm not sure. > > One thing which really helps is disabling preemption. If I do that, > I get 7.7Gb/sec with machdep.cpu_idle_hlt=1. This is slightly better > than machdep.cpu_idle_hlt=0 and no PREEMPTION. > > BTW, net.isr.direct=1 in all testing. Do you have very little userland activity in this test? -- John Baldwin <jhb_at_FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.orgReceived on Tue Feb 07 2006 - 21:43:23 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:38:52 UTC