Run via...

foreach file ( 10M 100M 1G 10G )
foreach? foreach pct ( 1 2 3 4 5 6 7 8 9 10 )
foreach? ../a.out $file $pct >> & test.txt
foreach? ../clearmem 730; sleep 3
foreach? end
foreach? end

..a.out is seqtest.c. clearmem is this:

/*
 * $Id: clearmem.c,v 1.1 2003/06/29 20:41:33 decibel Exp $
 *
 * Utility to clear out a chunk of memory and zero it. Useful for flushing disk buffers
 */

int main(int argc, char *argv[]) {
    if (!calloc(atoi(argv[1]), 1024*1024)) { printf("Error allocating memory.\n"); }
}

Reading 1% (12/1280 blocks 10485760 bytes) total time 74907us MB/s 1.31 effective MB/s 139.98
Reading 2% (25/1280 blocks 10485760 bytes) total time 133133us MB/s 1.54 effective MB/s 78.76
Reading 3% (38/1280 blocks 10485760 bytes) total time 187906us MB/s 1.66 effective MB/s 55.80
Reading 4% (51/1280 blocks 10485760 bytes) total time 158496us MB/s 2.64 effective MB/s 66.16
Reading 5% (64/1280 blocks 10485760 bytes) total time 176840us MB/s 2.96 effective MB/s 59.30
Reading 6% (76/1280 blocks 10485760 bytes) total time 170083us MB/s 3.66 effective MB/s 61.65
Reading 7% (89/1280 blocks 10485760 bytes) total time 184551us MB/s 3.95 effective MB/s 56.82
Reading 8% (102/1280 blocks 10485760 bytes) total time 173368us MB/s 4.82 effective MB/s 60.48
Reading 9% (115/1280 blocks 10485760 bytes) total time 196054us MB/s 4.81 effective MB/s 53.48
Reading 10% (128/1280 blocks 10485760 bytes) total time 178013us MB/s 5.89 effective MB/s 58.90
Reading 1% (128/12800 blocks 104857600 bytes) total time 855065us MB/s 1.23 effective MB/s 122.63
Reading 2% (256/12800 blocks 104857600 bytes) total time 1262796us MB/s 1.66 effective MB/s 83.04
Reading 3% (384/12800 blocks 104857600 bytes) total time 1569894us MB/s 2.00 effective MB/s 66.79
Reading 4% (512/12800 blocks 104857600 bytes) total time 1790379us MB/s 2.34 effective MB/s 58.57
Reading 5% (640/12800 blocks 104857600 bytes) total time 1808079us MB/s 2.90 effective MB/s 57.99
Reading 6% (768/12800 blocks 104857600 bytes) total time 3608305us MB/s 1.74 effective MB/s 29.06
Reading 7% (896/12800 blocks 104857600 bytes) total time 1845969us MB/s 3.98 effective MB/s 56.80
Reading 8% (1024/12800 blocks 104857600 bytes) total time 1877635us MB/s 4.47 effective MB/s 55.85
Reading 9% (1152/12800 blocks 104857600 bytes) total time 1961489us MB/s 4.81 effective MB/s 53.46
Reading 10% (1280/12800 blocks 104857600 bytes) total time 2604093us MB/s 4.03 effective MB/s 40.27
Reading 1% (1280/128000 blocks 1048576000 bytes) total time 8759689us MB/s 1.20 effective MB/s 119.70
Reading 2% (2560/128000 blocks 1048576000 bytes) total time 14724686us MB/s 1.42 effective MB/s 71.21
Reading 3% (3840/128000 blocks 1048576000 bytes) total time 16214562us MB/s 1.94 effective MB/s 64.67
Reading 4% (5120/128000 blocks 1048576000 bytes) total time 19091129us MB/s 2.20 effective MB/s 54.92
Reading 5% (6400/128000 blocks 1048576000 bytes) total time 22287356us MB/s 2.35 effective MB/s 47.05
Reading 6% (7680/128000 blocks 1048576000 bytes) total time 20911989us MB/s 3.01 effective MB/s 50.14
Reading 7% (8960/128000 blocks 1048576000 bytes) total time 26735770us MB/s 2.75 effective MB/s 39.22
Reading 8% (10240/128000 blocks 1048576000 bytes) total time 26432167us MB/s 3.17 effective MB/s 39.67
Reading 9% (11520/128000 blocks 1048576000 bytes) total time 23488590us MB/s 4.02 effective MB/s 44.64
Reading 10% (12800/128000 blocks 1048576000 bytes) total time 27407314us MB/s 3.83 effective MB/s 38.26
Reading 1% (12800/1280000 blocks 10485760000 bytes) total time 91128747us MB/s 1.15 effective MB/s 115.07
Reading 2% (25600/1280000 blocks 10485760000 bytes) total time 142194305us MB/s 1.47 effective MB/s 73.74
Reading 3% (38400/1280000 blocks 10485760000 bytes) total time 184682509us MB/s 1.70 effective MB/s 56.78
Reading 4% (51200/1280000 blocks 10485760000 bytes) total time 204736943us MB/s 2.05 effective MB/s 51.22
Reading 5% (64000/1280000 blocks 10485760000 bytes) total time 217606651us MB/s 2.41 effective MB/s 48.19
Reading 6% (76800/1280000 blocks 10485760000 bytes) total time 231965339us MB/s 2.71 effective MB/s 45.20
Reading 7% (89600/1280000 blocks 10485760000 bytes) total time 236010971us MB/s 3.11 effective MB/s 44.43
Reading 8% (102400/1280000 blocks 10485760000 bytes) total time 243517092us MB/s 3.44 effective MB/s 43.06
Reading 9% (115200/1280000 blocks 10485760000 bytes) total time 250622714us MB/s 3.77 effective MB/s 41.84
Reading 10% (128000/1280000 blocks 10485760000 bytes) total time 245938205us MB/s 4.26 effective MB/s 42.64

decibel@noel.2[8:51]~/tmp:47>dd if=10G of=/dev/null bs=8k
1280000+0 records in
1280000+0 records out
10485760000 bytes transferred in 253.023843 secs (41441786 bytes/sec)
decibel@noel.2[9:01]~/tmp:48>dd if=10G of=/dev/null bs=1m
10000+0 records in
10000+0 records out
10485760000 bytes transferred in 252.158686 secs (41583973 bytes/sec)
decibel@noel.2[9:07]~/tmp:49>