On Fri, Aug 22, 2014 at 9:03 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: >> > > If a GPU >> > > client uses only prelocations, the relocation process can be entirely >> > > skipped. This sounds like a big win initially, >> > >> > Close to zero if the client uses existing interfaces. >> > -Chris >> >> Chris, >> >> I don't know if you've seen Ben's libdrm and Mesa patches, but with a few patches to libdrm and virtually zero Mesa changes, he's apparently eliminated our need to do any relocations for the 3D driver. It wasn't invasive at all---I was surprised. > > Indeed, you could do everything inside libdrm with the code I posted 2 > years ago. I915_EXEC_NO_RELOC can be used to tell the kernel that it doesn't need to walk all the reloc tables (if nothing moved) because userspace didn't go insane and reuse reloc trees. So you'd need to implement a flag + a libdrm function to set that (iirc mesa has been non-stupid since years). And yeah I kinda expect any new reloc-less thing to get benchmarked against an implementation using that, since the 48bit specific thing proposed looks like a fairly short-lived stop-gap, and since the current no-reloc we already have would work everywhere. And yeah I've been poking people to look at this for years. too. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
