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| -rw-r--r-- | doc/README.440-DDR-performance | 90 |
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diff --git a/doc/README.440-DDR-performance b/doc/README.440-DDR-performance new file mode 100644 index 0000000..17bc747 --- /dev/null +++ b/doc/README.440-DDR-performance @@ -0,0 +1,90 @@ +AMCC suggested to set the PMU bit to 0 for best performace on the +PPC440 DDR controller. The 440er common DDR setup files (sdram.c & +spd_sdram.c) are changed accordingly. So all 440er boards using +these setup routines will automatically receive this performance +increase. + +Please see below some benchmarks done by AMCC to demonstrate this +performance changes: + + +---------------------------------------- +SDRAM0_CFG0[PMU] = 1 (U-boot default for Bamboo, Yosemite and Yellowstone) +---------------------------------------- +Stream benchmark results +------------------------------------------------------------- +This system uses 8 bytes per DOUBLE PRECISION word. +------------------------------------------------------------- +Array size = 2000000, Offset = 0 +Total memory required = 45.8 MB. +Each test is run 10 times, but only +the *best* time for each is used. +------------------------------------------------------------- +Your clock granularity/precision appears to be 1 microseconds. +Each test below will take on the order of 112345 microseconds. + (= 112345 clock ticks) +Increase the size of the arrays if this shows that you are not getting +at least 20 clock ticks per test. +------------------------------------------------------------- +WARNING -- The above is only a rough guideline. +For best results, please be sure you know the precision of your system +timer. +------------------------------------------------------------- +Function Rate (MB/s) RMS time Min time Max time +Copy: 256.7683 0.1248 0.1246 0.1250 +Scale: 246.0157 0.1302 0.1301 0.1302 +Add: 255.0316 0.1883 0.1882 0.1885 +Triad: 253.1245 0.1897 0.1896 0.1899 + + +TTCP Benchmark Results +ttcp-t: socket +ttcp-t: connect +ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000 tcp -> +localhost +ttcp-t: 16777216 bytes in 0.28 real seconds = 454.29 Mbit/sec +++ +ttcp-t: 2048 I/O calls, msec/call = 0.14, calls/sec = 7268.57 +ttcp-t: 0.0user 0.1sys 0:00real 60% 0i+0d 0maxrss 0+2pf 3+1506csw + +---------------------------------------- +SDRAM0_CFG0[PMU] = 0 (Suggested modification) +Setting PMU = 0 provides a noticeable performance improvement *2% to +5% improvement in memory performance. +*Improves the Mbit/sec for TTCP benchmark by almost 76%. +---------------------------------------- +Stream benchmark results +------------------------------------------------------------- +This system uses 8 bytes per DOUBLE PRECISION word. +------------------------------------------------------------- +Array size = 2000000, Offset = 0 +Total memory required = 45.8 MB. +Each test is run 10 times, but only +the *best* time for each is used. +------------------------------------------------------------- +Your clock granularity/precision appears to be 1 microseconds. +Each test below will take on the order of 120066 microseconds. + (= 120066 clock ticks) +Increase the size of the arrays if this shows that you are not getting +at least 20 clock ticks per test. +------------------------------------------------------------- +WARNING -- The above is only a rough guideline. +For best results, please be sure you know the precision of your system +timer. +------------------------------------------------------------- +Function Rate (MB/s) RMS time Min time Max time +Copy: 262.5167 0.1221 0.1219 0.1223 +Scale: 258.4856 0.1238 0.1238 0.1240 +Add: 262.5404 0.1829 0.1828 0.1831 +Triad: 266.8594 0.1800 0.1799 0.1802 + +TTCP Benchmark Results +ttcp-t: socket +ttcp-t: connect +ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000 tcp -> +localhost +ttcp-t: 16777216 bytes in 0.16 real seconds = 804.06 Mbit/sec +++ +ttcp-t: 2048 I/O calls, msec/call = 0.08, calls/sec = 12864.89 +ttcp-t: 0.0user 0.0sys 0:00real 46% 0i+0d 0maxrss 0+2pf 120+1csw + + +2006-07-28, Stefan Roese <sr@denx.de> |