<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [BDW Bisected] OglDrvCtx performance reduced by ~30% after use true PPGTT in Gen8+" href="https://bugs.freedesktop.org/show_bug.cgi?id=87726#c16">Comment # 16</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [BDW Bisected] OglDrvCtx performance reduced by ~30% after use true PPGTT in Gen8+" href="https://bugs.freedesktop.org/show_bug.cgi?id=87726">bug 87726</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>You would need to measure current mesa with execlists=0 and ppgtt=1 to get the current baseline. Baseline: i915.enable_execlists=0 i915.enable_ppgtt=1 # Not sure if i915.enable_execlists=0 i915.enable_ppgtt=2 is functional enough to # test 1: i915.enable_execlists=1 i915.enable_ppgtt=1 2: i915.enable_execlists=1 i915.enable_ppgtt=2 The biggest improvement in the kernel for this bug was from using an rbtree for vma lookup, and improving the mechanisms for writing the GTT. (Almost) Everything I had planned for this bug (since ~30 months ago) is almost in the kernel, the last dregs can be found here: <a href="https://cgit.freedesktop.org/~ickle/linux-2.6/log/?h=prescheduler">https://cgit.freedesktop.org/~ickle/linux-2.6/log/?h=prescheduler</a> (down to 37 patches!!!). The remaining features are O(1) lookup for vma from a context (i.e. excellent scaling of execbuf to very large number of contexts), context state caching.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> </ul> </body> </html>