On Tue, Jun 27, 2017 at 10:40 PM, Dave Airlie <airlied at gmail.com> wrote: > On 26 June 2017 at 19:10, zhoucm1 <david1.zhou at amd.com> wrote: >> >> >> On 2017å¹´06æ??26æ?¥ 03:48, Dave Airlie wrote: >>>> >>>> Do you not use bo list at all in mesa? radv as well? >>> >>> Currently radv is creating a bo list per command submission. radv does >>> not use an offload thread to do command submission, as it seems pretty >>> un-vulkan to use a thread for the queue submission thread the game >>> uses. >>> >>> I have considered investigating this, but with vulkan it's probably >>> optimising for the single threaded case which isn't where apps should >>> really be. >>> >>> At the moment we regenerate the bo list on every CS ioctl, we probably >>> can do a lot better, I know Bas has looked into this area a bit more >>> than I. >> >> Thanks Dave for inputting. >> >> Could I ask more about radv? How does radv make bo list for every cs ioctl? >> Adding filter in every operation, any related bo will be add to bo list >> during make command submission? > > When we create command buffers we add each bo to a list for it, but we > don't call the kernel ioctl. > > When we get a QueueSubmit, we usually submit two IBs to the kernel, > one with some cache flushes and one with the main IB in it, however as > we have to give the kernel one bo list we have to combine the two > lists (even if the cache flush list only has one ib in it, itself), so > we can't call create bo list early, we have to do it just before > command submission. However I don't think we've had any problems with > this being our slow path yet, but this may change in the future. Yeah. IIRC the bo list create is typically < 10% of our kernel time for radv. > > Dave.
