Josh Vanderhoof wrote:
>
> Adam Wiggins <[EMAIL PROTECTED]> writes:
>
> > Oh, they're more or less the same - the difference is that Intel's chips
> > have floating point which is comparable to their integer processing,
> > whereas AMD's K6's beat the pants off of Intel for integer, but lagged
> > way behind on floating point. 3DNow! was basically a quick fix to this
> > problem.
>
> You're probably right, but 3dnow is still capable of being faster than
> standard instructions. Here is how the different combinations compare
> in Mesa. The times are cycles to transform 100 points3_general
> vertices. (The K6-2 times are from Holger.)
>
> K6-2 without 3dnow: 11338
> K6-2 with 3dnow: 1993
> Plain old pentium: 4742
>
> Mesa running q3test spends a little more than 5% of its time in
> gl_x86_transform_points3_general on my Pentium (this may have changed
> slightly - I haven't profiled it lately), so the 3dnow version is
> probably around 2.5% faster if everything else is equal. SSE (I think
> this is the current name for KNI) should be similar.
>
> Clipping looks like the biggest bottleneck for q3test on Mesa right
> now.
This hasn't really been the case since the fxfastpath code was introduced. A
sample profile (from a *long* time ago, but more or less still correct) is
attached. Clipping is actually done in routines called called
render_vb_triangles_TMU0_TMU1 and also in fx_tri_clip_RGBA_TMU0 (the equivalent
routine is inlined in the TMU0_TMU1 case, which is why it doesn't show up).
Clipping is still a significant percentage, but it is not 'number 1'...
% cumulative self self total
time seconds seconds calls us/call us/call name
10.03 1.75 1.75 163106 10.73 10.73
gl_3dnow_transform_points3_general_raw_fx2
8.43 3.22 1.47 48173 30.52 30.52
render_vb_triangles_TMU0_TMU1
7.51 4.53 1.31 48173 27.19 27.19
fx_project_clipped_vertices_TMU0_TMU1
6.36 5.64 1.11 78776 14.09 24.82 fx_setup_full_RGBA_TMU0
5.62 6.62 0.98 207667 4.72 4.72 fx_tri_clip_RGBA_TMU0
5.56 7.59 0.97 gl_x86_FX_cliptest_points4
3.61 8.22 0.63 52804 11.93 11.93
fx_project_vertices_RGBA_TMU0
3.44 8.82 0.60 150301 3.99 3.99
render_vb_triangles_fx_smooth_indirect
3.10 9.36 0.54 80446 6.71 17.44 fx_setup_full_TMU0_TMU1
2.52 9.80 0.44 163106 2.70 2.70 gl_prepare_arrays_cva
Keith
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