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sched: make the multiplication table more accurate

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do small deltas in the weight and multiplication constant table so
that the worst-case numeric error is better than 1:100000000. (8 digits)

the current error table is:

     nice       mult *   inv_mult   error
     ------------------------------------------
     -20:      88761 *      48388  -0.0000000065
     -19:      71755 *      59856  -0.0000000037
     -18:      56483 *      76040   0.0000000056
     -17:      46273 *      92818   0.0000000042
     -16:      36291 *     118348  -0.0000000065
     -15:      29154 *     147320  -0.0000000037
     -14:      23254 *     184698  -0.0000000009
     -13:      18705 *     229616  -0.0000000037
     -12:      14949 *     287308  -0.0000000009
     -11:      11916 *     360437  -0.0000000009
     -10:       9548 *     449829  -0.0000000009
      -9:       7620 *     563644  -0.0000000037
      -8:       6100 *     704093   0.0000000009
      -7:       4904 *     875809   0.0000000093
      -6:       3906 *    1099582  -0.0000000009
      -5:       3121 *    1376151  -0.0000000058
      -4:       2501 *    1717300   0.0000000009
      -3:       1991 *    2157191  -0.0000000035
      -2:       1586 *    2708050   0.0000000009
      -1:       1277 *    3363326   0.0000000014
       0:       1024 *    4194304   0.0000000000
       1:        820 *    5237765   0.0000000009
       2:        655 *    6557202   0.0000000033
       3:        526 *    8165337  -0.0000000079
       4:        423 *   10153587   0.0000000012
       5:        335 *   12820798   0.0000000079
       6:        272 *   15790321   0.0000000037
       7:        215 *   19976592  -0.0000000037
       8:        172 *   24970740  -0.0000000037
       9:        137 *   31350126  -0.0000000079
      10:        110 *   39045157  -0.0000000061
      11:         87 *   49367440  -0.0000000037
      12:         70 *   61356676   0.0000000056
      13:         56 *   76695844  -0.0000000075
      14:         45 *   95443717  -0.0000000072
      15:         36 *  119304647  -0.0000000009
      16:         29 *  148102320  -0.0000000037
      17:         23 *  186737708  -0.0000000028
      18:         18 *  238609294  -0.0000000009
      19:         15 *  286331153  -0.0000000002

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-08-09 11:16:51 +02:00
parent 6e82a3befe
commit 254753dc32
1 changed files with 16 additions and 13 deletions
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29
kernel/sched.c
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@ -704,11 +704,14 @@ static void update_load_sub(struct load_weight *lw, unsigned long dec)
* the relative distance between them is ~25%.) * the relative distance between them is ~25%.)
*/ */
static const int prio_to_weight[40] = { static const int prio_to_weight[40] = {
/* -20 */ 88818, 71054, 56843, 45475, 36380, 29104, 23283, 18626, 14901, 11921, /* -20 */ 88761, 71755, 56483, 46273, 36291,
/* -10 */ 9537, 7629, 6103, 4883, 3906, 3125, 2500, 2000, 1600, 1280, /* -15 */ 29154, 23254, 18705, 14949, 11916,
/* 0 */ NICE_0_LOAD /* 1024 */, /* -10 */ 9548, 7620, 6100, 4904, 3906,
/* 1 */ 819, 655, 524, 419, 336, 268, 215, 172, 137, /* -5 */ 3121, 2501, 1991, 1586, 1277,
/* 10 */ 110, 87, 70, 56, 45, 36, 29, 23, 18, 15, /* 0 */ 1024, 820, 655, 526, 423,
/* 5 */ 335, 272, 215, 172, 137,
/* 10 */ 110, 87, 70, 56, 45,
/* 15 */ 36, 29, 23, 18, 15,
}; };
/* /*
@ -719,14 +722,14 @@ static const int prio_to_weight[40] = {
* into multiplications: * into multiplications:
*/ */
static const u32 prio_to_wmult[40] = { static const u32 prio_to_wmult[40] = {
/* -20 */ 48356, 60446, 75558, 94446, 118058, /* -20 */ 48388, 59856, 76040, 92818, 118348,
/* -15 */ 147573, 184467, 230589, 288233, 360285, /* -15 */ 147320, 184698, 229616, 287308, 360437,
/* -10 */ 450347, 562979, 703746, 879575, 1099582, /* -10 */ 449829, 563644, 704093, 875809, 1099582,
/* -5 */ 1374389, 1717986, 2147483, 2684354, 3355443, /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
/* 0 */ 4194304, 5244160, 6557201, 8196502, 10250518, /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
/* 5 */ 12782640, 16025997, 19976592, 24970740, 31350126, /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
/* 10 */ 39045157, 49367440, 61356675, 76695844, 95443717, /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
/* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
}; };
static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);