3 files changed, 152 insertions, 1 deletions

diff --git a/include/litmus/fpmath.h b/include/litmus/fpmath.h
new file mode 100644
index 000000000000..04d4bcaeae96
--- /dev/null
+++ b/include/litmus/fpmath.h
@@ -0,0 +1,145 @@
+#ifndef __FP_MATH_H__
+#define __FP_MATH_H__
+
+#ifndef __KERNEL__
+#include <stdint.h>
+#define abs(x) (((x) < 0) ? -(x) : x)
+#endif
+
+// Use 64-bit because we want to track things at the nanosecond scale.
+// This can lead to very large numbers.
+typedef int64_t fpbuf_t;
+typedef struct
+{
+        fpbuf_t val;
+} fp_t;
+
+#define FP_SHIFT 10
+#define ROUND_BIT (FP_SHIFT - 1)
+
+#define _fp(x) ((fp_t) {x})
+
+#ifdef __KERNEL__
+static const fp_t LITMUS_FP_ZERO = {.val = 0};
+static const fp_t LITMUS_FP_ONE = {.val = (1 << FP_SHIFT)};
+#endif
+
+static inline fp_t FP(fpbuf_t x)
+{
+        return _fp(((fpbuf_t) x) << FP_SHIFT);
+}
+
+/* divide two integers to obtain a fixed point value  */
+static inline fp_t _frac(fpbuf_t a, fpbuf_t b)
+{
+        return _fp(FP(a).val / (b));
+}
+
+static inline fpbuf_t _point(fp_t x)
+{
+        return (x.val % (1 << FP_SHIFT));
+
+}
+
+#define fp2str(x) x.val
+/*(x.val >> FP_SHIFT), (x.val % (1 << FP_SHIFT)) */
+#define _FP_  "%ld/1024"
+
+static inline fpbuf_t _floor(fp_t x)
+{
+        return x.val >> FP_SHIFT;
+}
+
+/* FIXME: negative rounding */
+static inline fpbuf_t _round(fp_t x)
+{
+        return _floor(x) + ((x.val >> ROUND_BIT) & 1);
+}
+
+/* multiply two fixed point values */
+static inline fp_t _mul(fp_t a, fp_t b)
+{
+        return _fp((a.val * b.val) >> FP_SHIFT);
+}
+
+static inline fp_t _div(fp_t a, fp_t b)
+{
+#if !defined(__KERNEL__) && !defined(unlikely)
+#define unlikely(x) (x)
+#define DO_UNDEF_UNLIKELY
+#endif
+        /* try not to overflow */
+        if (unlikely(  a.val > (2l << ((sizeof(fpbuf_t)*8) - FP_SHIFT)) ))
+                return _fp((a.val / b.val) << FP_SHIFT);
+        else
+                return _fp((a.val << FP_SHIFT) / b.val);
+#ifdef DO_UNDEF_UNLIKELY
+#undef unlikely
+#undef DO_UNDEF_UNLIKELY
+#endif
+}
+
+static inline fp_t _add(fp_t a, fp_t b)
+{
+        return _fp(a.val + b.val);
+}
+
+static inline fp_t _sub(fp_t a, fp_t b)
+{
+        return _fp(a.val - b.val);
+}
+
+static inline fp_t _neg(fp_t x)
+{
+        return _fp(-x.val);
+}
+
+static inline fp_t _abs(fp_t x)
+{
+        return _fp(abs(x.val));
+}
+
+/* works the same as casting float/double to integer */
+static inline fpbuf_t _fp_to_integer(fp_t x)
+{
+        return _floor(_abs(x)) * ((x.val > 0) ? 1 : -1);
+}
+
+static inline fp_t _integer_to_fp(fpbuf_t x)
+{
+        return _frac(x,1);
+}
+
+static inline int _leq(fp_t a, fp_t b)
+{
+        return a.val <= b.val;
+}
+
+static inline int _geq(fp_t a, fp_t b)
+{
+        return a.val >= b.val;
+}
+
+static inline int _lt(fp_t a, fp_t b)
+{
+        return a.val < b.val;
+}
+
+static inline int _gt(fp_t a, fp_t b)
+{
+        return a.val > b.val;
+}
+
+static inline int _eq(fp_t a, fp_t b)
+{
+        return a.val == b.val;
+}
+
+static inline fp_t _max(fp_t a, fp_t b)
+{
+        if (a.val < b.val)
+                return b;
+        else
+                return a;
+}
+#endif
diff --git a/include/litmus/litmus.h b/include/litmus/litmus.h
index 338245abd6ed..807b7888695a 100644
--- a/include/litmus/litmus.h
+++ b/include/litmus/litmus.h
@@ -63,7 +63,7 @@ void litmus_exit_task(struct task_struct *tsk);
 #define get_exec_time(t)    (tsk_rt(t)->job_params.exec_time)
 #define get_deadline(t)         (tsk_rt(t)->job_params.deadline)
 #define get_release(t)          (tsk_rt(t)->job_params.release)
-
+#define get_lateness(t)         (tsk_rt(t)->job_params.lateness)
 
 #define is_hrt(t)               \
         (tsk_rt(t)->task_params.cls == RT_CLASS_HARD)
diff --git a/include/litmus/rt_param.h b/include/litmus/rt_param.h
index 89ac0dda7d3d..fac939dbd33a 100644
--- a/include/litmus/rt_param.h
+++ b/include/litmus/rt_param.h
@@ -110,6 +110,12 @@ struct rt_job {
         /* How much service has this job received so far? */
         lt_t    exec_time;
 
+        /* By how much did the prior job miss its deadline by?
+         * Value differs from tardiness in that lateness may
+         * be negative (when job finishes before its deadline).
+         */
+        long long       lateness;
+
         /* Which job is this. This is used to let user space
          * specify which job to wait for, which is important if jobs
          * overrun. If we just call sys_sleep_next_period() then we