added process scheduling algorithms

2024-12-02 22:56:33 +01:00
parent fe957e03d1
commit 32473b67bc
9 changed files with 634 additions and 0 deletions
--- a/process-scheduling/algorithms/srtf.typ
+++ b/process-scheduling/algorithms/srtf.typ
@@ -0,0 +1,155 @@
+#import "utils.typ": *
+
+#let remtime-add(list, task) = {
+  let left-i = list.rev()
+                   .position(t => t.remaining > task.remaining)
+  
+  if left-i == none {
+    left-i = list.rev()
+                 .position(t => t.arrival > task.arrival)
+  }
+
+  let i = if left-i == none {
+    0
+  } else {
+    list.len() - left-i
+  }
+  if task.pid == 7 {
+    let dbg = (list, task, i)
+  }
+  list.insert(i, task)
+  return list
+}
+
+#let SRTF(tasks, ctx-switch: 1) = {
+  let (processes, tasks) = _prepare-tasks(tasks)
+  tasks = tasks.rev()
+
+  let n-tasks = tasks.len()
+  let cur-time = 0
+  let current = none
+  let finished = 0
+  let remtime-list = ()
+  let logs = ()
+
+  while finished != n-tasks {
+    let log = "Current time: " + str(cur-time) + " / "
+    if (current != none) {
+        log += "Current: " + str(current.pid) + " / "
+    } else {
+        log += "Current: none / "
+    }
+    if (tasks.len() != 0) {
+        log += "Next: " + str(tasks.last().pid)
+    } else {
+        log += "Next: none"
+    }
+    logs.push(log)
+
+    if current == none {
+      current = tasks.pop()
+      logs.push("No running process: running " + str(current.pid))
+      current.state = RUNNING
+      processes.at(current.id).events.push((RUNNING, current.arrival))
+
+    } else if tasks.len() != 0 {
+      logs.push(log-list(remtime-list))
+      logs.push("Processing next process (" + str(tasks.last().pid) + ")")
+      tasks.last().state = READY
+      let delta = tasks.last().arrival - cur-time
+
+      while current != none and current.remaining <= delta {
+        logs.push("  Process " + str(current.pid) + " finished before next")
+        if current.state != RUNNING {
+          processes.at(current.id).events.push((RUNNING, cur-time))
+        }
+        current.state = TERMINATED
+        cur-time += current.remaining
+        delta = tasks.last().arrival - cur-time
+        current.remaining = 0
+        processes.at(current.id).events.push((TERMINATED, cur-time))
+        finished += 1
+        if remtime-list.len() != 0 {
+          current = remtime-list.pop()
+        } else {
+          current = none
+        }
+      }
+
+      if current != none {
+        logs.push("Removing time from current process")
+        if current.state != RUNNING and tasks.last().arrival > cur-time {
+          processes.at(current.id).events.push((RUNNING, cur-time))
+          current.state = RUNNING
+          //processes.at(current.id).events.push((READY, tasks.last().arrival))
+        }
+        current.remaining -= delta
+        logs.push("  New remaining time " + str(current.remaining))
+      }
+      if tasks.last().arrival > cur-time {
+        cur-time = tasks.last().arrival
+      }
+      tasks.last().state = READY
+
+      if current == none {
+        current = tasks.pop()
+        logs.push("Queue is empty, running next process " + str(current.pid))
+        current.state = RUNNING
+        processes.at(current.id).events.push((RUNNING, cur-time))
+      
+      } else if tasks.last().remaining < current.remaining {
+        logs.push("Next process (" + str(tasks.last().pid) + ") has shorter remaining time")
+        if current.state != READY {
+          processes.at(current.id).events.push((READY, cur-time))
+        }
+        if current.state == RUNNING {
+          logs.push("  Preempting current process (" + str(current.pid) +")")
+          current.remaining -= tasks.last().arrival - cur-time
+          processes.at(tasks.last().id).events.push((READY, cur-time))
+          cur-time += ctx-switch
+        }
+        if current.state == RUNNING {
+          current.state = READY
+          remtime-list = remtime-add(remtime-list, current)
+        } else {
+          remtime-list.push(current)
+        }
+
+        current = tasks.pop()
+
+        current.state = RUNNING
+        processes.at(current.id).events.push((RUNNING, cur-time))
+      } else {
+        logs.push("Adding next process (" + str(tasks.last().pid) + ") to list")
+        processes.at(tasks.last().id).events.push((READY, cur-time))
+        remtime-list = remtime-add(remtime-list, tasks.pop())
+      }
+      if current != none {
+        if current.state != RUNNING {
+          processes.at(current.id).events.push((RUNNING, cur-time))
+        }
+        current.state = RUNNING
+      }
+    } else {
+      logs.push("No new processes, emptying queue")
+      logs.push(log-list(remtime-list))
+      while current != none {
+        logs.push("Completing process " + str(current.pid))
+        current.state = TERMINATED
+        cur-time += current.remaining
+        current.remaining = 0
+        processes.at(current.id).events.push((TERMINATED, cur-time))
+        finished += 1
+        if remtime-list.len() != 0 {
+          current = remtime-list.pop()
+          current.state = RUNNING
+          processes.at(current.id).events.push((RUNNING, cur-time))
+        } else {
+          current = none
+        }
+      }
+    }
+  }
+
+  return _prepare-output(processes)
+}