Hi, I did some benchmarking and measurements of the memory controller's real performance (the system now has an additional core which measures that). Here are the results of the idle system (demo firmware started, no preset rendering, video output enabled 640x...@60hz) and when rendering some presets.
The performance of the memory system is reasonable (it's not excellent, but it doesn't suck either and probably exceeds that of all other free designs). It might still be improved: it seems that it could go up to approximately only half of the peak bandwidth of the chips (with this access pattern). This is encouraging to experiment with an out-of-order memory controller in the far future (Milkymist 2.x). Does anyone have typical results of proprietary SDRAM controllers to compare? Sébastien Idle: Net memory bandwidth : 293 Mbps Memory bus occupancy : 7% Extrapolated max bandwith: 4185 Mbps Avg. mem. access time : 5.52 cycles Geiss - Bright Fiber Matrix 1: Net memory bandwidth : 1067 Mbps Memory bus occupancy : 31% Extrapolated max bandwith: 3441 Mbps Avg. mem. access time : 6.58 cycles Geiss - Swirlie 3: Net memory bandwidth : 1160 Mbps Memory bus occupancy : 34% Extrapolated max bandwith: 3411 Mbps Avg. mem. access time : 6.71 cycles StudioMusic - Twisted Galaxy: Net memory bandwidth : 942 Mbps Memory bus occupancy : 25% Extrapolated max bandwith: 3768 Mbps Avg. mem. access time : 5.94 cycles Geiss - Spacedust: Net memory bandwidth : 1024 Mbps Memory bus occupancy : 30% Extrapolated max bandwith: 3413 Mbps Avg. mem. access time : 6.67 cycles Geiss - Anomaly 2: Net memory bandwidth : 1127 Mbps Memory bus occupancy : 33% Extrapolated max bandwith: 3415 Mbps Avg. mem. access time : 6.58 cycles Aderrasi - Candy Avian: Net memory bandwidth : 923 Mbps Memory bus occupancy : 27% Extrapolated max bandwith: 3418 Mbps Avg. mem. access time : 6.52 cycles _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkym...@freenode Webchat: www.milkymist.org/irc.html Wiki: www.milkymist.org/wiki
