Re: [PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt

[Peter Zijlstra]

On Tue, May 03, 2016 at 05:54:32AM +0800, Yuyang Du wrote:
> This doc file has the programs to generate the constants to compute
> sched averages.
> 
> Signed-off-by: Yuyang Du 
> ---
>  Documentation/scheduler/sched-avg.txt |  137 
> +
>  1 file changed, 137 insertions(+)
>  create mode 100644 Documentation/scheduler/sched-avg.txt
> 
> diff --git a/Documentation/scheduler/sched-avg.txt 
> b/Documentation/scheduler/sched-avg.txt
> new file mode 100644
> index 000..ae4132f
> --- /dev/null
> +++ b/Documentation/scheduler/sched-avg.txt
> @@ -0,0 +1,137 @@
> +The following programs are used to generate the constants for
> +computing sched averages.
> +
> +==
> + C program (compile with -lm)
> +==

> +==
> + Python script if you speak snake
> +==

Please do not put two programs in one file. Also, I think I would prefer
it to be one program; having two just means they can drift apart and
create confusion.

Re: [PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt

[Peter Zijlstra]

On Tue, May 03, 2016 at 05:54:32AM +0800, Yuyang Du wrote:
> This doc file has the programs to generate the constants to compute
> sched averages.
> 
> Signed-off-by: Yuyang Du 
> ---
>  Documentation/scheduler/sched-avg.txt |  137 
> +
>  1 file changed, 137 insertions(+)
>  create mode 100644 Documentation/scheduler/sched-avg.txt
> 
> diff --git a/Documentation/scheduler/sched-avg.txt 
> b/Documentation/scheduler/sched-avg.txt
> new file mode 100644
> index 000..ae4132f
> --- /dev/null
> +++ b/Documentation/scheduler/sched-avg.txt
> @@ -0,0 +1,137 @@
> +The following programs are used to generate the constants for
> +computing sched averages.
> +
> +==
> + C program (compile with -lm)
> +==

> +==
> + Python script if you speak snake
> +==

Please do not put two programs in one file. Also, I think I would prefer
it to be one program; having two just means they can drift apart and
create confusion.

[PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt

[Yuyang Du]

This doc file has the programs to generate the constants to compute
sched averages.

Signed-off-by: Yuyang Du 
---
 Documentation/scheduler/sched-avg.txt |  137 +
 1 file changed, 137 insertions(+)
 create mode 100644 Documentation/scheduler/sched-avg.txt

diff --git a/Documentation/scheduler/sched-avg.txt 
b/Documentation/scheduler/sched-avg.txt
new file mode 100644
index 000..ae4132f
--- /dev/null
+++ b/Documentation/scheduler/sched-avg.txt
@@ -0,0 +1,137 @@
+The following programs are used to generate the constants for
+computing sched averages.
+
+==
+   C program (compile with -lm)
+==
+
+#include 
+#include 
+
+#define HALFLIFE 32
+#define SHIFT 32
+
+double y;
+
+void calc_decay_inv_multiply() {
+   int i;
+   unsigned int x;
+
+   printf("static const u32 __decay_inv_multiply_N[] = {");
+   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_accumulated_sum() {
+   int i;
+
+   printf("static const u32 __accumulated_sum_N[] = {\n\t0,");
+   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() {
+   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 SCHED_AVG_HALFLIFE %d\n", HALFLIFE);
+   printf("#define SCHED_AVG_MAX %ld\n", max);
+   printf("#define SCHED_AVG_MAX_N %d\n\n", n);
+}
+
+void calc_accumulated_sum_32() {
+   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() {
+   y = pow(0.5, 1/(double)HALFLIFE);
+
+   calc_decay_inv_multiply();
+   calc_accumulated_sum();
+   calc_converged_max();
+   calc_accumulated_sum_32();
+}
+
+==
+   Python script if you speak snake
+==
+
+#!/usr/bin/env python
+
+print " #: yN_inv   yN_sum"
+print "---"
+y = (0.5)**(1/32.0)
+x = 2**32
+xx = 1024
+for i in range(0, 32):
+   if i == 0:
+   x = x-1
+   xx = xx*y
+   else:
+   x = x*y
+   xx = int(xx*y + 1024*y)
+   print "%2d: %#x %8d" % (i, int(x), int(xx))
+
+print
+print " #:  sum_N32"
+print ""
+xxx = xx
+for i in range(0, 11):
+   if i > 0:
+   xxx = xxx/2 + xx
+   print "%2d: %8d" % (i, xxx)
+
+print
+print "  n: max"
+print ""
+ = 1024
+old = 0
+i = 2
+while (1):
+    = int(*y + 1024)
+   if old == :
+   break
+   i = i+1
+   old = 
+print "%3d: %7d" % (i-1, )
-- 
1.7.9.5

[PATCH v2 06/12] documentation: Add scheduler/sched-avg.txt

[Yuyang Du]

This doc file has the programs to generate the constants to compute
sched averages.

Signed-off-by: Yuyang Du 
---
 Documentation/scheduler/sched-avg.txt |  137 +
 1 file changed, 137 insertions(+)
 create mode 100644 Documentation/scheduler/sched-avg.txt

diff --git a/Documentation/scheduler/sched-avg.txt 
b/Documentation/scheduler/sched-avg.txt
new file mode 100644
index 000..ae4132f
--- /dev/null
+++ b/Documentation/scheduler/sched-avg.txt
@@ -0,0 +1,137 @@
+The following programs are used to generate the constants for
+computing sched averages.
+
+==
+   C program (compile with -lm)
+==
+
+#include 
+#include 
+
+#define HALFLIFE 32
+#define SHIFT 32
+
+double y;
+
+void calc_decay_inv_multiply() {
+   int i;
+   unsigned int x;
+
+   printf("static const u32 __decay_inv_multiply_N[] = {");
+   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_accumulated_sum() {
+   int i;
+
+   printf("static const u32 __accumulated_sum_N[] = {\n\t0,");
+   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() {
+   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 SCHED_AVG_HALFLIFE %d\n", HALFLIFE);
+   printf("#define SCHED_AVG_MAX %ld\n", max);
+   printf("#define SCHED_AVG_MAX_N %d\n\n", n);
+}
+
+void calc_accumulated_sum_32() {
+   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() {
+   y = pow(0.5, 1/(double)HALFLIFE);
+
+   calc_decay_inv_multiply();
+   calc_accumulated_sum();
+   calc_converged_max();
+   calc_accumulated_sum_32();
+}
+
+==
+   Python script if you speak snake
+==
+
+#!/usr/bin/env python
+
+print " #: yN_inv   yN_sum"
+print "---"
+y = (0.5)**(1/32.0)
+x = 2**32
+xx = 1024
+for i in range(0, 32):
+   if i == 0:
+   x = x-1
+   xx = xx*y
+   else:
+   x = x*y
+   xx = int(xx*y + 1024*y)
+   print "%2d: %#x %8d" % (i, int(x), int(xx))
+
+print
+print " #:  sum_N32"
+print ""
+xxx = xx
+for i in range(0, 11):
+   if i > 0:
+   xxx = xxx/2 + xx
+   print "%2d: %8d" % (i, xxx)
+
+print
+print "  n: max"
+print ""
+ = 1024
+old = 0
+i = 2
+while (1):
+    = int(*y + 1024)
+   if old == :
+   break
+   i = i+1
+   old = 
+print "%3d: %7d" % (i-1, )
-- 
1.7.9.5