https://bugs.freedesktop.org/show_bug.cgi?id=33934
--- Comment #3 from Neil Roberts <n...@linux.intel.com> 2011-02-08 05:08:06 PST --- Created an attachment (id=43096) --> (https://bugs.freedesktop.org/attachment.cgi?id=43096) Test case showing the performance difference Well at least on the Intel driver there is a faster path for blitting that glCopyTexSubImage2D uses. If it's not also beneficial for Radeon then maybe we should move the patch to be specific to the Intel drivers. Attached is a test case to get some timing for the two functions. Without patch: time for glBlitFramebuffer = 122285 time for glCopyTexSubImage2D = 6097 So glCopyTexSubImage2D is 1906% faster than glBlitFramebuffer. With the patch I get: time for glBlitFramebuffer = 25740 time for glCopyTexSubImage2D = 6900 The patch improves the speed of glBlitFramebuffer by 375% but it's still pretty slow compared to glCopyTexSubImage2D. Maybe the cost of glBlitFramebuffer is mostly in preserving the GL state across the Mesa meta calls and the patch still does a bit of this. Maybe we should make a proper Intel-specific fast path for glBlitFramebuffer that directly calls intelEmitCopyBlit like do_copy_texsubimage does so that it can avoid affecting the GL state. -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
