On Wednesday 05 April 2006 17:40, Julian Elischer wrote: > John Baldwin wrote: > > >On Tuesday 04 April 2006 20:33, Paolo Pisati wrote: > > > > > >>Hi, > >> > >>i updated my work on interrupt profiling with sone new > >>experiments. > >> > >>In total we have now: > >> > >>-FreeBSD 4 PIC (no asm part) > >>-FreeBSD 7 APIC > >>-FreeBSD 7 PIC > >>-FreeBSD 7 PREE APIC > >>-FreeBSD 7 APIC JHB > >> > >>Some quick comments: > >> > >>-PIC is much slower in masking interrupt (7k in PIC vs 3k in APIC) > >>-PREE let new thread save less than 500 ticks of 'queue' while > >> preempted threads are often resumed after a lot > >>-JHB patch shaved 2.5k ticks in interrupt masking op > >> > >>For graphs, data and more comments: > >> > >>http://mercurio.sm.dsi.unimi.it/~pisati/interrupt/ > >> > >> > > > >I'll commit the patch then. :) One thing you might try to do to better > >measure the effects of preemption is to generate kernel work so that > >the bge interrupts occur while the current thread is in the kernel > >rather than in userland. In that case preemption should provide much > >lower latency for interrupt handlers, as w/o preemption, an interrupt > >in kernel mode won't run the ithread until either curthread blocks or > >returns to userland. > > > > > > it looks a bit like the preempted threads shuld be put onto a stack of > threads to resume > so that when the pre-empter finishes, teh previosly active thread is > resumed. > Basically, a preempted thread should be put at the HEAD of it's run > queue, and not the tail.. You changed the scheduler to already do that. -- John Baldwin <jhb_at_FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.orgReceived on Thu Apr 06 2006 - 17:11:06 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:38:54 UTC