2.5.66 fbdev performance (was Re: Re: FBdev updates)

From: Petr Vandrovec (vandrove@vc.cvut.cz)
Date: Fri Mar 28 2003 - 09:19:28 EST


Hello,
  I see a problem with new pixmap based code...
There is 25% slowdown for 8x16 8bpp videomode
after upgrading from 2.5.63 to 2.5.66 :-(

Setup as usual, 1024x768, 100Hz, secondary
head doing nothing (i.e. no fbtv...), CPU
doing nothing except running this test.
P4 1.6GHz, MGA G550. Shown value is system
time in seconds needed to repaint screen 1000
times (avg. from 3 tests) (you can treat it
as time in milliseconds needed to repaint
screen once).

Although speedup for 12x22 font is very nice,
it looks to me that we paid too much for it.

Problem is in the new pixmap handling, especially
pixbuf.output - so now instead of memcpy we
call some function for copying each byte from
font to temporary buffer. As you can see,
"constant" portion of time, independent of
color depth, increased by 1sec for unaccelerated
and by 0.75sec for accelerated putcs.
It is 5% to 25% slowdown (5% for 32bpp unaccelerated,
25% for 8bpp accelerated).

And while we are still faster than 2.4.x, we were
even better...
                                Petr

NOACCEL, 8x16
        2.4.19+fbtv 2.5.63+fbtv 2.5.63 2.5.66
8bpp 10.02 6.96 5.62 6.62
16bpp 20.05 13.25 10.62 11.63
24bpp 30.03 19.05 15.13 16.07
32bpp 45.00 25.74 20.54 21.62

ACCEL, 8x16
        2.4.19+fbtv 2.5.63+fbtv 2.5.63 2.5.66
8bpp 7.48 3.38 3.00 3.75
16bpp 7.50 3.38 3.01 3.76
24bpp 7.53 3.56 3.53 4.23
32bpp 8.95 4.37 4.33 5.05

NOACCEL, 12x22
        2.4.19+fbtv 2.5.63+fbtv 2.5.63 2.5.66
8bpp 11.54 13.35 10.93 8.96
16bpp 20.00 22.02 18.03 13.61
24bpp 30.03 35.83 29.53 18.07
32bpp 40.12 44.48 36.75 23.22

ACCEL, 12x22
        2.4.19+fbtv 2.5.63+fbtv 2.5.63 2.5.66
8bpp 8.57 14.87 12.90 5.72
16bpp 8.57 14.93 12.92 5.72
24bpp 8.56 15.13 13.10 6.20
32bpp 8.56 15.52 13.76 6.98

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