Commit-ID: 76d034edcf658e3c74fd90b149882ab1464e4af9 Gitweb: http://git.kernel.org/tip/76d034edcf658e3c74fd90b149882ab1464e4af9 Author: Yuyang Du <yuyang...@intel.com> AuthorDate: Mon, 13 Feb 2017 05:44:22 +0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 14 Apr 2017 10:26:35 +0200
sched/Documentation: Add 'sched-pelt' tool 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...@intel.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Mike Galbraith <efa...@gmx.de> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: bseg...@google.com Cc: dietmar.eggem...@arm.com Cc: m...@codeblueprint.co.uk Cc: morten.rasmus...@arm.com Cc: p...@google.com Cc: umgwanakikb...@gmail.com Cc: vincent.guit...@linaro.org Link: http://lkml.kernel.org/r/1486935863-25251-2-git-send-email-yuyang...@intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- Documentation/scheduler/sched-pelt.c | 108 +++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/Documentation/scheduler/sched-pelt.c b/Documentation/scheduler/sched-pelt.c new file mode 100644 index 0000000..e421913 --- /dev/null +++ b/Documentation/scheduler/sched-pelt.c @@ -0,0 +1,108 @@ +/* + * The following program is used to generate the constants for + * computing sched averages. + * + * ============================================================== + * C program (compile with -lm) + * ============================================================== + */ + +#include <math.h> +#include <stdio.h> + +#define HALFLIFE 32 +#define SHIFT 32 + +double y; + +void calc_runnable_avg_yN_inv(void) +{ + int i; + unsigned int x; + + printf("static const u32 runnable_avg_yN_inv[] = {"); + for (i = 0; i < HALFLIFE; i++) { + x = ((1UL<<32)-1)*pow(y, i); + + if (i % 6 == 0) printf("\n\t"); + printf("0x%8x, ", x); + } + printf("\n};\n\n"); +} + +int sum = 1024; + +void calc_runnable_avg_yN_sum(void) +{ + int i; + + printf("static const u32 runnable_avg_yN_sum[] = {\n\t 0,"); + for (i = 1; i <= HALFLIFE; i++) { + if (i == 1) + sum *= y; + else + sum = sum*y + 1024*y; + + if (i % 11 == 0) + printf("\n\t"); + + printf("%5d,", sum); + } + printf("\n};\n\n"); +} + +int n = -1; +/* first period */ +long max = 1024; + +void calc_converged_max(void) +{ + long last = 0, y_inv = ((1UL<<32)-1)*y; + + for (; ; n++) { + if (n > -1) + max = ((max*y_inv)>>SHIFT) + 1024; + /* + * This is the same as: + * max = max*y + 1024; + */ + + if (last == max) + break; + + last = max; + } + n--; + printf("#define LOAD_AVG_PERIOD %d\n", HALFLIFE); + printf("#define LOAD_AVG_MAX %ld\n", max); +// printf("#define LOAD_AVG_MAX_N %d\n\n", n); +} + +void calc_accumulated_sum_32(void) +{ + int i, x = sum; + + printf("static const u32 __accumulated_sum_N32[] = {\n\t 0,"); + for (i = 1; i <= n/HALFLIFE+1; i++) { + if (i > 1) + x = x/2 + sum; + + if (i % 6 == 0) + printf("\n\t"); + + printf("%6d,", x); + } + printf("\n};\n\n"); +} + +void main(void) +{ + printf("/* Generated by Documentation/scheduler/sched-pelt; do not modify. */\n\n"); + + y = pow(0.5, 1/(double)HALFLIFE); + + calc_runnable_avg_yN_inv(); +// calc_runnable_avg_yN_sum(); + calc_converged_max(); +// calc_accumulated_sum_32(); +}
