Linked by Thom Holwerda on Sat 28th Jun 2008 22:09 UTC, submitted by diegocg
X11, Window Managers "Maybe I'm just naive, but designing a graphics API such that all image data had to be sent over a socket to another process every time the image needed to be drawn seems like complete idiocy. Unfortunately, that is precisely what the X Window System forces a program to do, and exactly what Cairo does when drawing images in Linux - a full copy of the image data, send to another process, no less, every time it is drawn. One would think there would be some room for improvement. Unsurprisingly, others felt the same way about X, and decided to write an extension, Xlib Shm or XShm for short, that allows images to placed in a shared memory segment from which the X server reads which allows the program to avoid the memory copy. GTK already makes use of the XShm extension, and it seems like a good idea to see if Gecko couldn't do the same."
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RE[5]: Exaggerating
by Ekorn on Sun 29th Jun 2008 14:55 UTC in reply to "RE[4]: Exaggerating"
Ekorn
Member since:
2006-03-17

This is interesting, running Debian Lenny on a Core2 Duo 2,4GHz with integrated Intel GMA965 :

$ time x11perf -putimage500
x11perf - X11 performance program, version 1.2
The X.Org Foundation server version 10400090 on :0.0
from yggdrasil
Sun Jun 29 17:02:43 2008

Sync time adjustment is 0.0228 msecs.

8000 reps @ 0.7075 msec ( 1410.0/sec): PutImage 500x500 square
8000 reps @ 0.6736 msec ( 1480.0/sec): PutImage 500x500 square
8000 reps @ 0.6596 msec ( 1520.0/sec): PutImage 500x500 square
8000 reps @ 0.6818 msec ( 1470.0/sec): PutImage 500x500 square
8000 reps @ 0.6738 msec ( 1480.0/sec): PutImage 500x500 square
40000 trep @ 0.6793 msec ( 1470.0/sec): PutImage 500x500 square


real 0m33.953s
user 0m9.421s
sys 0m9.337s

$ time x11perf -shmput500
x11perf - X11 performance program, version 1.2
The X.Org Foundation server version 10400090 on :0.0
from yggdrasil
Sun Jun 29 17:03:29 2008

Sync time adjustment is 0.0230 msecs.

8000 reps @ 0.9115 msec ( 1100.0/sec): ShmPutImage 500x500 square
8000 reps @ 0.9155 msec ( 1090.0/sec): ShmPutImage 500x500 square
8000 reps @ 0.9105 msec ( 1100.0/sec): ShmPutImage 500x500 square
8000 reps @ 0.9106 msec ( 1100.0/sec): ShmPutImage 500x500 square
8000 reps @ 0.9121 msec ( 1100.0/sec): ShmPutImage 500x500 square
40000 trep @ 0.9120 msec ( 1100.0/sec): ShmPutImage 500x500 square


real 0m43.488s
user 0m0.356s
sys 0m0.728s


Edit: Added 'time' to the commands.

Edited 2008-06-29 15:04 UTC

Reply Parent Score: 1