iosched: impact of streaming write on streaming read

From: Andrew Morton (akpm@digeo.com)
Date: Fri Feb 21 2003 - 00:27:03 EST

Here we take a look at the impact which a streaming write has upon streaming
read bandwidth.

A single streaming write was set up with:

        while true
        do
                dd if=/dev/zero of=foo bs=1M count=512 conv=notrunc
        done

and we measure how long it takes to read a 100 megabyte file from the same
filesystem with

        time cat 100m-file > /dev/null

I'll include `vmstat 1' snippets here as well.

2.4.21-pre4: 42 seconds
 1 3 276 4384 2144 222300 0 0 80 26480 520 743 0 6 94 0
 0 3 276 4344 2144 222240 0 0 76 25224 512 492 0 4 96 0
 0 3 276 4340 2148 222220 0 0 124 25584 520 536 0 3 97 0
 0 3 276 4404 2152 222132 0 0 44 26604 538 533 0 5 95 0
 0 4 276 4464 2160 221928 0 0 60 25040 516 559 0 4 96 0
 0 4 276 4460 2160 221900 0 0 612 27456 560 621 0 4 96 0
 0 4 276 4392 2156 221972 0 0 708 23872 488 566 0 4 95 0
 0 4 276 4420 2168 221852 0 0 688 26668 545 653 0 4 96 0
 0 4 276 4204 2164 221912 0 0 696 21588 492 884 0 5 95 0
 0 4 276 4448 2164 221668 0 0 396 21376 423 833 0 4 96 0
 0 4 276 4432 2160 221688 0 0 784 26368 544 705 0 4 96 0
 0 4 276 4400 2168 221608 0 0 560 27640 563 596 0 5 95 0
 4 1 276 4324 2188 221616 0 0 12476 12996 538 908 0 4 96 0
 0 4 276 3516 2196 222408 0 0 12320 16048 529 971 0 2 98 0
 0 4 276 3468 2212 222424 0 0 12704 14428 540 1039 0 4 96 0
 0 4 276 4112 2208 221700 0 0 552 20824 474 539 0 4 96 0
 3 2 276 3768 2208 222040 0 0 524 25428 503 612 0 3 97 0
 0 4 276 4452 2216 221344 0 0 536 19548 437 1241 0 3 97 0

2.5.61+hacks: 48 seconds
 0 5 0 2140 1296 227700 0 0 0 22236 1213 126 0 4 0 96
 0 5 0 2252 1296 227664 0 0 0 23340 1219 123 0 3 0 97
 0 6 0 4044 1288 225904 0 0 1844 13632 1183 236 0 2 0 98
 0 6 0 4100 1268 225788 0 0 1920 13780 1173 217 0 2 0 98
 0 6 0 4156 1248 225908 0 0 2184 14828 1184 236 0 3 0 97
 0 6 0 4100 1244 226012 0 0 2176 13720 1173 237 0 2 0 98
 0 6 0 4212 1240 225980 0 0 1924 13900 1175 236 0 2 0 98
 0 5 0 5444 1192 224824 0 0 2304 11820 1164 206 0 2 0 98
 0 6 0 2196 1180 228088 0 0 2308 14460 1180 269 0 3 0 97

2.5.61+CFQ: 27 seconds
 1 3 0 6196 2060 222852 0 0 0 23840 1247 220 0 4 4 92
 0 2 0 4404 1820 224880 0 0 0 22208 1237 271 0 3 8 89
 2 4 0 2884 1680 226588 0 0 1496 26944 1263 355 0 4 2 94
 0 4 0 4332 1312 225388 0 0 4592 14692 1244 414 0 3 0 97
 0 4 0 4268 1012 225764 0 0 1408 29540 1308 671 0 5 0 95
 0 4 0 3316 1016 226752 0 0 2820 27500 1306 668 0 5 0 95
 0 4 0 4212 992 225924 0 0 3076 22148 1255 508 0 3 0 97

2.5.61+AS: 3.8 seconds
 0 4 0 2236 1320 227548 0 0 0 36684 1335 136 0 5 0 95
 0 4 0 2236 1296 227636 0 0 0 37736 1334 134 0 5 0 95
 0 5 0 3348 1088 226604 0 0 1232 30040 1320 174 0 4 0 96
 0 5 0 2284 1056 227920 0 0 29088 5488 1536 855 0 4 0 96
 0 5 0 4916 1080 225672 0 0 26904 8452 1517 993 0 5 0 95
 0 5 120 2228 1108 228732 0 120 29472 6752 1545 940 0 3 1 96
 0 4 120 4196 1060 226984 0 0 16164 15740 1426 627 0 3 3 93
        

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This archive was generated by hypermail 2b29 : Sun Feb 23 2003 - 22:00:32 EST