From e2876ba7587083ba0de27d33bd58547cdc3cc52b Mon Sep 17 00:00:00 2001
From: Blinningjr <nicke.l@telia.com>
Date: Sat, 2 Jan 2021 16:55:25 +0100
Subject: [PATCH] Implemented exact preemptions
---
srp_analysis/src/main.rs | 67 +++++++++++++++++++++++-----------------
1 file changed, 38 insertions(+), 29 deletions(-)
diff --git a/srp_analysis/src/main.rs b/srp_analysis/src/main.rs
index 8ba2019..fa13577 100644
--- a/srp_analysis/src/main.rs
+++ b/srp_analysis/src/main.rs
@@ -74,7 +74,7 @@ fn main() {
println!("ip: {:?}", ip);
println!("tr: {:?}", tr);
- let analysis = analyse(&tasks, &ip, &tr);
+ let analysis = analyse(&tasks, &ip, &tr, true);
println!("Analysis {:#?}", analysis);
}
@@ -124,9 +124,9 @@ fn wcet(trace: &Trace) -> u32 {
* - B(t) is the blocking time for task t, and
* - I(t) is the interference (preemptions) to task t
*/
-fn response_time(task: &Task, tasks: &Tasks, ip: &IdPrio, tr: &TaskResources) -> u32 {
- let r: u32 = block_time(task, tasks, ip, tr) + wcet(&task.trace) + interference_time(task, tasks);
- println!("response_time {:?}", r);
+fn response_time(task: &Task, tasks: &Tasks, ip: &IdPrio, tr: &TaskResources, approx: bool) -> u32 {
+ let r: u32 = block_time(task, tasks, ip, tr) + wcet(&task.trace) + interference_time(task, tasks, ip, tr, approx).unwrap();
+ //println!("response_time {:?}", r);
return r;
}
@@ -194,7 +194,7 @@ fn block_time(task: &Task, tasks: &Tasks, ip: &IdPrio, tr: &TaskResources) -> u3
}
}
- println!("block time {:?}", block_time);
+ //println!("block time {:?}", block_time);
return block_time;
}
@@ -208,28 +208,37 @@ fn block_time(task: &Task, tasks: &Tasks, ip: &IdPrio, tr: &TaskResources) -> u3
* Note: I(t) = sum(C(h) * ceiling(Bp(t)/A(h))), forall tasks h, P(h) > P(t), where
* Bp(t) is the busy-period
*/
-fn interference_time(task: &Task, tasks: &Tasks) -> u32 {
- let mut interference: u32 = 0;
- for t in tasks {
- if t.prio > task.prio {
- interference += wcet(&t.trace) * (((busy_period(t) as f32) / (t.inter_arrival as f32)).ceil() as u32);
- }
- }
-
- println!("interference_time {:?}", interference);
- return interference;
-}
-
+fn interference_time(task: &Task, tasks: &Tasks, ip: &IdPrio, tr: &TaskResources, approx: bool) -> Result<u32, String> {
+ fn calc_interference(task: &Task, tasks: &Tasks, busy_period: u32) -> u32 {
+ let mut interference: u32 = 0;
+ for t in tasks {
+ if t.prio > task.prio {
+ interference += wcet(&t.trace) * (((busy_period as f32) / (t.inter_arrival as f32)).ceil() as u32);
+ }
+ }
+ return interference;
+ }
-/*
- * Caclulates the busy period of task t(Bp(t)).
- * Bp(t)
- *
- * Note: We can over approximate the busy period Bp(i) = D(i) (assuming the worst allowed busy-period).
- * D(i) is the deadline of task i.
- */
-fn busy_period(task: &Task) -> u32 {
- return task.deadline;
+ if approx {
+ let interference: u32 = calc_interference(task, tasks, task.deadline);
+ //println!("interference_time {:?}", interference);
+ return Ok(interference);
+ } else {
+ let constant = block_time(task, tasks, ip, tr) + wcet(&task.trace);
+ let mut busy_period: u32 = constant + calc_interference(task, tasks, constant);
+ loop {
+ if busy_period > task.deadline {
+ return Err("Busy period is longer then deadline".to_string());
+ } else {
+ let new_busy_period: u32 = constant + calc_interference(task, tasks, busy_period);
+ if busy_period == new_busy_period {
+ return Ok(new_busy_period - constant);
+ } else {
+ busy_period = new_busy_period;
+ }
+ }
+ }
+ }
}
@@ -239,13 +248,13 @@ fn busy_period(task: &Task) -> u32 {
* Note: Finally, make a function that iterates over the task set and returns a vector with containing:
Vec<Task, R(t), C(t), B(t), I(t)>. Just a simple println! of that vector gives the essential information on the analysis.
*/
-fn analyse(tasks: &Tasks, ip: &IdPrio, tr: &TaskResources) -> Vec<(Task, u32, u32, u32, u32)> {
+fn analyse(tasks: &Tasks, ip: &IdPrio, tr: &TaskResources, approx: bool) -> Vec<(Task, u32, u32, u32, u32)> {
let mut analysis: Vec<(Task, u32, u32, u32, u32)> = vec!();
for t in tasks {
- let r_t = response_time(t, tasks, ip, tr);
+ let r_t = response_time(t, tasks, ip, tr, approx);
let c_t = wcet(&t.trace);
let b_t = block_time(t, tasks, ip, tr);
- let i_t = interference_time(t, tasks);
+ let i_t = interference_time(t, tasks, ip, tr, approx).unwrap();
analysis.push((t.clone(), r_t, c_t, b_t, i_t));
}
return analysis;
--
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