u-boot/doc/README.440-DDR-performance

1 AMCC suggested to set the PMU bit to 0 for best performace on the
2 PPC440 DDR controller. The 440er common DDR setup files (sdram.c &
11 ----------------------------------------
12 SDRAM0_CFG0[PMU] = 1 (U-Boot default for Bamboo, Yosemite and Yellowstone)
13 ----------------------------------------
15 -------------------------------------------------------------
17 -------------------------------------------------------------
22 -------------------------------------------------------------
28 -------------------------------------------------------------
29 WARNING -- The above is only a rough guideline.
32 -------------------------------------------------------------
41 ttcp-t: socket
42 ttcp-t: connect
43 ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000  tcp  ->
45 ttcp-t: 16777216 bytes in 0.28 real seconds = 454.29 Mbit/sec +++
46 ttcp-t: 2048 I/O calls, msec/call = 0.14, calls/sec = 7268.57
47 ttcp-t: 0.0user 0.1sys 0:00real 60% 0i+0d 0maxrss 0+2pf 3+1506csw
49 ----------------------------------------
50 SDRAM0_CFG0[PMU] = 0 (Suggested modification)
51 Setting PMU = 0 provides a noticeable performance improvement *2% to
54 ----------------------------------------
56 -------------------------------------------------------------
58 -------------------------------------------------------------
63 -------------------------------------------------------------
69 -------------------------------------------------------------
70 WARNING -- The above is only a rough guideline.
73 -------------------------------------------------------------
81 ttcp-t: socket
82 ttcp-t: connect
83 ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000  tcp  ->
85 ttcp-t: 16777216 bytes in 0.16 real seconds = 804.06 Mbit/sec +++
86 ttcp-t: 2048 I/O calls, msec/call = 0.08, calls/sec = 12864.89
87 ttcp-t: 0.0user 0.0sys 0:00real 46% 0i+0d 0maxrss 0+2pf 120+1csw
90 2006-07-28, Stefan Roese <sr@denx.de>