Runnable threads on run queue

From: Ask List
Date: Sat Jul 08 2006 - 17:03:41 EST

Have an issue maybe someone on this list can help with.

At times of very high load the number of processes on the run queue drops to
0 then jumps really high and then drops to 0 and back and forth. It seems to
last 10 seconds or so. If you look at this vmstat you can see an example of
what I mean. Now im not a linux kernel expert but i am thinking it has
something to do with the scheduling algorithm and locking of the run queue.
For this particular application I need all available threads to be processed as
fast as possible. Is there a way for me to elimnate this behavior or at least
minimize the window in which there are no threads on the run queue? Is there a
sysctl parameter I can use?

Please help.

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
83 0 1328 301684 37868 1520632 0 0 0 264 400 1332 98 2 0 0
17 0 1328 293936 37868 1520688 0 0 0 0 537 979 97 3 0 0
73 0 1328 293688 37868 1520712 0 0 0 0 268 2643 98 2 0 0
80 0 1328 277220 37868 1520756 0 0 0 0 351 824 98 2 0 0
49 0 1328 262452 37868 1520800 0 0 0 0 393 1882 97 3 0 0
45 0 1328 246796 37868 1520828 0 0 0 304 302 1631 96 4 0 0
55 0 1328 243852 37868 1520872 0 0 0 0 356 1101 99 1 0 0
17 0 1328 228672 37868 1520916 0 0 0 0 336 748 97 3 0 0
0 0 1328 299948 37868 1520956 0 0 0 0 299 821 78 3 19 0
0 0 1328 299184 37868 1520960 0 0 0 0 168 78 8 0 92 0
0 0 1328 299184 37868 1520960 0 0 0 248 173 38 0 1 99 0
0 0 1328 299184 37868 1520960 0 0 0 0 160 20 0 0 100 0
0 0 1328 299184 37868 1520960 0 0 0 0 151 6 0 0 100 0
0 0 1328 299184 37868 1520960 0 0 0 0 162 42 0 1 99 0
1 0 1328 299188 37868 1520960 0 0 0 0 161 24 0 0 100 0
0 0 1328 298808 37868 1520988 0 0 0 100 303 1119 57 0 42 0
0 0 1328 298808 37868 1520988 0 0 0 0 162 22 0 1 99 0
3 0 1328 298808 37868 1520992 0 0 0 0 195 233 16 0 84 0
14 0 1328 298788 37868 1521032 0 0 0 0 400 1158 87 3 10 0
54 0 1328 298860 37868 1521064 0 0 0 0 438 940 97 3 0 0
80 0 1328 298296 37868 1521092 0 0 0 180 476 556 97 3 0 0
29 0 1328 294632 37868 1521148 0 0 0 0 824 1178 99 1 0 0
68 0 1328 292936 37868 1521172 0 0 0 0 404 2283 96 4 0 0
73 0 1328 292740 37868 1521216 0 0 0 0 521 828 98 2 0 0
38 0 1328 260340 37868 1521260 0 0 0 0 405 1069 96 4 0 0
46 0 1328 253072 37868 1521292 0 0 0 300 371 1692 95 5 0 0
71 0 1328 244084 37868 1521328 0 0 0 0 357 1478 98 2 0 0
71 0 1328 233916 37868 1521384 0 0 0 0 528 1121 97 3 0 0
32 0 1328 222784 37868 1521416 0 0 0 0 347 1191 96 4 0 0
76 0 1328 212396 37868 1521448 0 0 0 0 337 2526 97 3 0 0
71 0 1328 198684 37868 1521488 0 0 0 284 497 942 98 2 0 0
40 0 1328 189964 37868 1521532 0 0 0 0 420 1525 96 4 0 0
53 0 1328 179656 37868 1521576 0 0 0 0 391 1983 98 2 0 0
91 0 1328 169164 37868 1521608 0 0 0 0 415 2018 98 2 0 0
70 0 1328 151300 37868 1521648 0 0 0 0 411 1769 98 2 0 0
43 0 1328 145980 37868 1521684 0 0 0 308 420 1713 96 4 0 0
48 0 1328 142708 37868 1521724 0 0 0 0 290 1490 97 3 0 0
76 0 1328 126080 37868 1521752 0 0 0 0 389 1568 97 3 0 0
85 0 1328 120544 37864 1518164 0 0 0 0 365 1261 96 4 0 0
51 0 1328 121312 37864 1506908 0 0 0 0 306 1217 98 2 0 0
55 0 1328 121488 37864 1495128 0 0 0 292 364 1976 98 2 0 0
79 0 1328 120408 37864 1486072 0 0 0 0 328 2106 97 3 0 0
29 0 1328 216660 37864 1482744 0 0 0 0 387 866 97 3 0 0
0 0 1328 321932 37864 1482788 0 0 0 0 289 750 67 3 31 0
0 0 1328 321932 37864 1482788 0 0 0 0 158 10 0 0 100 0
2 0 1328 321912 37864 1482792 0 0 0 268 201 156 4 1 94 0
0 0 1328 321892 37864 1482796 0 0 0 0 180 270 7 0 93 0
0 0 1328 321892 37864 1482796 0 0 0 0 152 4 0 0 100 0
0 0 1328 321880 37864 1482796 0 0 0 0 158 26 0 1 99 0
0 0 1328 321844 37864 1482820 0 0 0 0 330 454 41 1 58 0
0 0 1328 321844 37864 1482820 0 0 0 120 167 30 0 0 100 0
0 0 1328 321844 37864 1482820 0 0 0 0 166 35 1 0 99 0
35 0 1328 321476 37864 1482836 0 0 0 0 530 1026 67 2 31 0
76 0 1328 321528 37868 1482864 0 0 0 0 406 1744 96 4 0 0
41 0 1328 321172 37868 1482920 0 0 0 192 409 690 97 3 0 0
34 0 1328 314788 37868 1482956 0 0 0 0 356 1616 97 3 0 0
63 0 1328 314368 37868 1482996 0 0 0 0 437 1277 98 2 0 0
1 0 1328 331744 37868 1483044 0 0 0 0 331 709 90 3 7 0
0 0 1328 331724 37868 1483048 0 0 0 0 174 395 4 0 96 0
0 0 1328 331724 37868 1483048 0 0 0 224 168 16 0 0 100 0
0 0 1328 331724 37868 1483048 0 0 0 0 167 54 0 1 99 0
7 0 1328 331744 37868 1483048 0 0 0 0 238 167 10 0 90 0
46 0 1328 330788 37868 1483076 0 0 0 0 878 1677 98 2 0 0
84 0 1328 330444 37868 1483100 0 0 0 0 425 1449 97 3 0 0

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