OK. I see. Thanks Michel! :) Have a nice day. :) Thanks, Zhi. > -----Original Message----- > From: Thierry, Michel > Sent: Wednesday, November 25, 2015 9:15 PM > To: Wang, Zhi A; intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: Han, Xu; Li, Weinan Z; He, Min; Lv, Zhiyuan; Tian, Kevin > Subject: Re: About dealing with CSB.context element switch in > execlist mode. > > On 11/25/2015 1:00 PM, Wang, Zhi A wrote: > > Another question about EXECLIST is: Can a preemption happen between > element switch? > > > > I know this is beyond the scope of i915 a little. I'm just curious if it's possible. > > > > Let's say we have context A B C > > > > At first, we submit context A B in one ELSP write. > > Then, we submit context C in another ELSP write at some time. > > > > If context A or B is running and gets preempted, then there will be > CSB.preempted in CSB buffer. This is the normal behavior. > > > > I'm wondering that if there is any possibility that a preemption can happen > between the two elements. > > > > Then the CSB should look like: > > > > [CSB 0 idle-to-active] > > [CSB 1 CTX A element_switch/context_complete] [CSB 2 CTX C > > active-to-idle/context_complete] > > > > Is it possible? > > I would expect to always have a preempted event in the CSB, even in the > remote case that A already completed and B hasn't started; there was an > active execlist and it has been replaced by a new one: > > [CSB 0 idle-to-active] > [CSB 1 CTX A element_switch/context_complete] > [CSB 2 preempted ] > [CSB 3 CTX C active-to-idle/context_complete] _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
