76d034edcf
Add a user-space program to compute/generate the PELT constants. The kernel/sched/sched-pelt.h header will contain the output of this program. Signed-off-by: Yuyang Du <yuyang.du@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: matt@codeblueprint.co.uk Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1486935863-25251-2-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
109 lines
1.9 KiB
C
109 lines
1.9 KiB
C
/*
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* The following program is used to generate the constants for
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* computing sched averages.
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*
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* ==============================================================
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* C program (compile with -lm)
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* ==============================================================
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*/
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#include <math.h>
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#include <stdio.h>
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#define HALFLIFE 32
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#define SHIFT 32
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double y;
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void calc_runnable_avg_yN_inv(void)
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{
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int i;
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unsigned int x;
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printf("static const u32 runnable_avg_yN_inv[] = {");
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for (i = 0; i < HALFLIFE; i++) {
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x = ((1UL<<32)-1)*pow(y, i);
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if (i % 6 == 0) printf("\n\t");
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printf("0x%8x, ", x);
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}
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printf("\n};\n\n");
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}
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int sum = 1024;
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void calc_runnable_avg_yN_sum(void)
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{
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int i;
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printf("static const u32 runnable_avg_yN_sum[] = {\n\t 0,");
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for (i = 1; i <= HALFLIFE; i++) {
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if (i == 1)
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sum *= y;
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else
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sum = sum*y + 1024*y;
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if (i % 11 == 0)
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printf("\n\t");
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printf("%5d,", sum);
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}
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printf("\n};\n\n");
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}
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int n = -1;
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/* first period */
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long max = 1024;
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void calc_converged_max(void)
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{
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long last = 0, y_inv = ((1UL<<32)-1)*y;
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for (; ; n++) {
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if (n > -1)
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max = ((max*y_inv)>>SHIFT) + 1024;
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/*
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* This is the same as:
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* max = max*y + 1024;
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*/
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if (last == max)
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break;
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last = max;
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}
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n--;
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printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE);
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printf("#define LOAD_AVG_MAX %ld\n", max);
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// printf("#define LOAD_AVG_MAX_N %d\n\n", n);
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}
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void calc_accumulated_sum_32(void)
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{
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int i, x = sum;
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printf("static const u32 __accumulated_sum_N32[] = {\n\t 0,");
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for (i = 1; i <= n/HALFLIFE+1; i++) {
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if (i > 1)
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x = x/2 + sum;
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if (i % 6 == 0)
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printf("\n\t");
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printf("%6d,", x);
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}
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printf("\n};\n\n");
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}
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void main(void)
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{
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printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n");
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y = pow(0.5, 1/(double)HALFLIFE);
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calc_runnable_avg_yN_inv();
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// calc_runnable_avg_yN_sum();
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calc_converged_max();
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// calc_accumulated_sum_32();
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}
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