{"id":65,"date":"2025-01-08T03:46:56","date_gmt":"2025-01-08T03:46:56","guid":{"rendered":"https:\/\/mitalgoswami.in\/?p=65"},"modified":"2025-07-17T06:51:09","modified_gmt":"2025-07-17T06:51:09","slug":"round-robin-rr-algorithm","status":"publish","type":"post","link":"https:\/\/mitalgoswami.in\/?p=65","title":{"rendered":"Round Robin (RR Algorithm)"},"content":{"rendered":"\n

Example:<\/strong><\/h3>\n\n\n\n

Given Processes:<\/h4>\n\n\n\n
Process<\/th>Arrival Time<\/th>Burst Time<\/th><\/tr><\/thead>
P1<\/td>0<\/td>6<\/td><\/tr>
P2<\/td>1<\/td>8<\/td><\/tr>
P3<\/td>2<\/td>7<\/td><\/tr>
P4<\/td>3<\/td>3<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Time Quantum: 4<\/h4>\n\n\n\n
\n\n\n\n

Step 1: Process Execution<\/strong><\/h4>\n\n\n\n
    \n
  1. At t=0<\/code>, P1 gets the CPU for 4 units. Remaining burst time: 2.<\/li>\n\n\n\n
  2. At t=4<\/code>, P2 executes for 4 units. Remaining burst time: 4.<\/li>\n\n\n\n
  3. At t=8<\/code>, P3 executes for 4 units. Remaining burst time: 3.<\/li>\n\n\n\n
  4. At t=12<\/code>, P4 executes for 3 units. Remaining burst time: 0 (P4 finishes).<\/li>\n\n\n\n
  5. Back to P1, executes for 2 units (finishes at t=17<\/code>).<\/li>\n\n\n\n
  6. P2 resumes, executes for 4 units (finishes at t=21<\/code>).<\/li>\n\n\n\n
  7. P3 resumes, executes for 3 units (finishes at t=24<\/code>).<\/li>\n<\/ol>\n\n\n\n
    \n\n\n\n

    Gantt Chart<\/strong><\/h4>\n\n\n\n

    | Time | 0 – 4 | 4 – 8 | 8 – 12 | 12 – 15 | 15 – 17 | 17 – 21 | 21 – 24 | |——|——-|——-|——–|———|———|———| | P | P1 | P2 | P3 | P4 | P1 | P2 | P3 |<\/p>\n\n\n\n

    \n\n\n\n

    Step 2: Calculations<\/strong><\/h4>\n\n\n\n

    Turnaround Time (TAT)<\/strong> = Completion Time – Arrival Time
    Waiting Time (WT)<\/strong> = Turnaround Time – Burst Time<\/p>\n\n\n\n

    Process<\/th>Arrival Time<\/th>Burst Time<\/th>Completion Time<\/th>TAT<\/th>WT<\/th><\/tr><\/thead>
    P1<\/td>0<\/td>6<\/td>17<\/td>17<\/td>11<\/td><\/tr>
    P2<\/td>1<\/td>8<\/td>21<\/td>20<\/td>12<\/td><\/tr>
    P3<\/td>2<\/td>7<\/td>24<\/td>22<\/td>15<\/td><\/tr>
    P4<\/td>3<\/td>3<\/td>15<\/td>12<\/td>9<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
    \n\n\n\n

    Step 3: Averages<\/strong><\/h4>\n\n\n\n
      \n
    • Average Turnaround Time (TAT):<\/strong> 17+20+22+124=17.75\\frac{17 + 20 + 22 + 12}{4} = 17.75417+20+22+12\u200b=17.75<\/li>\n\n\n\n
    • Average Waiting Time (WT):<\/strong> 11+12+15+94=11.75\\frac{11 + 12 + 15 + 9}{4} = 11.75411+12+15+9\u200b=11.75<\/li>\n<\/ul>\n\n\n\n
      \n\n\n\n

      Advantages of Round Robin<\/strong><\/h3>\n\n\n\n
        \n
      1. Fair for all processes.<\/li>\n\n\n\n
      2. Prevents starvation.<\/li>\n\n\n\n
      3. Simple to implement.<\/li>\n<\/ol>\n\n\n\n

        Disadvantages of Round Robin<\/strong><\/h3>\n\n\n\n
          \n
        1. High context switching overhead.<\/li>\n\n\n\n
        2. Performance depends heavily on the time quantum:\n
            \n
          • A very small quantum increases overhead.<\/li>\n\n\n\n
          • A very large quantum reduces responsiveness and approximates FCFS scheduling.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

            Example: Given Processes: Process Arrival Time Burst Time P1 0 6 P2 1 8 P3 2 7 P4 3 3 Time Quantum: 4 Step 1: Process Execution Gantt Chart | Time | 0 – 4 | 4 – 8 | 8 – 12 | 12 – 15 | 15 – 17 | 17 – 21 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-65","post","type-post","status-publish","format-standard","hentry","category-unix"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/posts\/65","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=65"}],"version-history":[{"count":1,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/posts\/65\/revisions"}],"predecessor-version":[{"id":66,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=\/wp\/v2\/posts\/65\/revisions\/66"}],"wp:attachment":[{"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=65"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=65"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mitalgoswami.in\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=65"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}