- \n
- \u9759\u6001\u4f18\u5148\u6743: \u9759\u6001\u4f18\u5148\u6743\u662f\u5728\u521b\u5efa\u8fdb\u7a0b\u65f6\u786e\u5b9a\u7684\uff0c\u5728\u6574\u4e2a\u8fd0\u884c\u671f\u95f4\u4e0d\u518d\u6539\u53d8\u3002\u4f9d\u636e\u6709\uff1a \u8fdb\u7a0b\u7c7b\u578b\u3001\u8fdb\u7a0b\u5bf9\u8d44\u6e90\u7684\u8981\u6c42\u3001\u7528\u6237\u8981\u6c42\u7684\u4f18\u5148\u6743\u3002<\/span><\/li>\n
- \u52a8\u6001\u4f18\u5148\u6743: \u52a8\u6001\u4f18\u5148\u6743\u662f\u57fa\u4e8e\u67d0\u79cd\u539f\u5219\uff0c\u4f7f\u8fdb\u7a0b\u7684\u4f18\u5148\u6743\u968f\u65f6\u95f4\u6539\u53d8\u800c\u6539\u53d8\u3002<\/span><\/li>\n<\/ul>\n
Default\uff1a\u6570\u5b57\u8d8a\u5c0f\uff0c\u4f18\u5148\u7ea7\u8d8a\u9ad8<\/span><\/p>\n
Example 1\uff08\u975e\u62a2\u5360\uff09\uff1a<\/span><\/p>\n
<\/span><\/p>\n
Example 2\uff08\u62a2\u5360\uff09\uff1a<\/span><\/p>\n
\u9700\u8981\u5b9e\u65f6\u5224\u65ad\u4f18\u5148\u7ea7\/\u4e0d\u540c\u65f6\u52a0\u5165<\/span><\/p>\n
<\/span><\/p>\n
\u7f3a\u70b9\uff1a\u9965\u997f<\/span>\uff08starvation\uff09<\/span><\/p>\n
\u65b9\u6cd5\uff1a\u8001\u5316<\/span>\uff08aging\uff09as time progresses increase the priority of the process.\u2014\u52a8\u6001\u4f18\u5148\u7ea7<\/span><\/p>\n
<\/p>\n
4.\u65f6\u95f4\u7247\u8f6e\u8f6c\u8c03\u5ea6 Round Robin (RR)<\/p>\n
- \n
- \u57fa\u672c\u601d\u8def\uff1a\u901a\u8fc7\u65f6\u95f4\u7247\u8f6e\u8f6c\uff0c\u63d0\u9ad8\u8fdb\u7a0b\u5e76\u53d1\u6027\u548c\u54cd\u5e94\u65f6\u95f4\u7279\u6027\uff0c\u4ece\u800c\u63d0\u9ad8\u8d44 \u6e90\u5229\u7528\u7387\u3002<\/span><\/li>\n
- RR\u7b97\u6cd5\uff1a<\/span>\n
- \n
- \u5c06\u7cfb\u7edf\u4e2d\u6240\u6709\u7684\u5c31\u7eea\u8fdb\u7a0b\u6309\u7167FCFS\u539f\u5219\uff0c\u6392\u6210\u4e00\u4e2a\u961f\u5217\u3002<\/span><\/li>\n
- \u6bcf\u6b21\u8c03\u5ea6\u65f6\u5c06CPU\u5206\u6d3e\u7ed9\u961f\u9996\u8fdb\u7a0b\uff0c\u8ba9\u5176\u6267\u884c\u4e00\u4e2a\u65f6\u95f4\u7247 (time slice) \u3002\u65f6\u95f4\u7247\u7684\u957f\u5ea6\u4ece \u51e0\u4e2ams\u5230\u51e0\u767ems\u3002<\/span><\/li>\n
- \u5728\u4e00\u4e2a\u65f6\u95f4\u7247\u7ed3\u675f\u65f6\uff0c\u53d1\u751f\u65f6\u949f\u4e2d\u65ad\u3002<\/span><\/li>\n
- \u8c03\u5ea6\u7a0b\u5e8f\u636e\u6b64\u6682\u505c\u5f53\u524d\u8fdb\u7a0b\u7684\u6267\u884c\uff0c\u5c06\u5176\u9001\u5230\u5c31\u7eea\u961f\u5217\u7684\u672b\u5c3e\uff0c\u5e76\u901a\u8fc7\u4e0a\u4e0b\u6587\u5207\u6362\u6267\u884c \u5f53\u524d\u7684\u961f\u9996\u8fdb\u7a0b\u3002<\/span><\/li>\n
- \u8fdb\u7a0b\u53ef\u4ee5\u672a\u4f7f\u7528\u5b8c\u4e00\u4e2a\u65f6\u95f4\u7247\uff0c\u5c31\u51fa\u8ba9CPU\uff08\u5982\u963b\u585e\uff09\u3002<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
If there are n processes in the ready queue and the time quantum is q, then each process gets 1\/n of the CPU time in chunks of at most q time units at once. No process waits more than (n-1)q time units.<\/span><\/p>\n
\u5982\u679c\u5c31\u7eea\u961f\u5217\u4e2d\u6709n\u4e2a\u8fdb\u7a0b\uff0c\u5e76\u4e14\u65f6\u95f4\u91cf\u4e3aq\uff0c\u5219\u6bcf\u4e2a\u8fdb\u7a0b\u4e00\u6b21\u6700\u591a\u4ee5q\u4e2a\u65f6\u95f4\u5355\u4f4d\u7684\u5757\u83b7\u53d6CPU\u65f6\u95f4\u76841 \/ n\u3002 \u6ca1\u6709\u8fdb\u7a0b\u7b49\u5f85\u8d85\u8fc7\uff08n-1\uff09q\u4e2a\u65f6\u95f4\u5355\u4f4d\u3002<\/span><\/p><\/blockquote>\n
\n\n\n\n\n\n\n<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n- \n
- Performance\n
- \n
- q large ->FIFO\/\/\u5148\u5230\u5148\u670d\u52a1<\/li>\n
- q small ->q must be large with respect to context switch<\/span>, otherwise overhead is too high\/\/\u5229\u7528\u7387\u4f4e<\/li>\n<\/ul>\n<\/li>\n
- \u65f6\u95f4\u7247\u957f\u5ea6\u7684\u5f71\u54cd\u56e0\u7d20\uff1a\n
- \n
- \u5c31\u7eea\u8fdb\u7a0b\u7684\u6570\u76ee\uff1a\u6570\u76ee\u8d8a\u591a\uff0c\u65f6\u95f4\u7247\u8d8a\u5c0f\uff08\u5f53\u54cd\u5e94\u65f6\u95f4\u4e00\u5b9a\u65f6\uff09<\/li>\n
- \u7cfb\u7edf\u7684\u5904\u7406\u80fd\u529b\uff1a\u5e94\u5f53\u4f7f\u7528\u6237\u8f93\u5165\u901a\u5e38\u5728\u4e00\u4e2a\u65f6\u95f4\u7247\u5185\u80fd\u5904\u7406\u5b8c\uff0c\u5426\u5219\u4f7f\u54cd\u5e94\u65f6\u95f4\uff0c\u5e73 \u5747\u5468\u8f6c\u65f6\u95f4\u548c\u5e73\u5747\u5e26\u6743\u5468\u8f6c\u65f6\u95f4\u5ef6\u957f\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
Example with Time quantum = 20<\/p>\n
<\/p>\n
<\/p>\n
5.\u591a\u7ea7\u961f\u5217\u8c03\u5ea6 Multilevel Queue Scheduling<\/p>\n
\u6839\u636e\u8fdb\u7a0b\u7684\u6027\u8d28\u6216\u7c7b\u578b\u7684\u4e0d\u540c\uff0c\u5c06\u5c31\u7eea\u961f\u5217\u518d\u5206\u4e3a\u82e5\u5e72\u4e2a\u5b50\u961f\u5217\u3002<\/span><\/p>\n
\u6bcf\u4e2a\u4f5c\u4e1a\u56fa\u5b9a\u5f52\u5165\u4e00\u4e2a\u961f\u5217\u3002<\/span><\/p>\n
\u5404\u961f\u5217\u7684\u4e0d\u540c\u5904\u7406\uff1a\u4e0d\u540c\u961f\u5217\u53ef\u6709\u4e0d\u540c\u7684\u4f18\u5148\u7ea7\u3001\u65f6\u95f4\u7247\u957f\u5ea6\u3001\u8c03\u5ea6\u7b56\u7565\u7b49 \u3002\u5982\uff1a\u7cfb\u7edf\u8fdb\u7a0b\u3001\u7528\u6237\u4ea4\u4e92\u8fdb\u7a0b\u3001\u6279\u5904\u7406\u8fdb\u7a0b\u7b49\u3002<\/span><\/p><\/blockquote>\n
- \n
- Ready queue is partitioned into separate queues:<\/span>\n
- \n
- foreground (interactive) \u524d\u53f0\uff08\u4ea4\u4e92\u5f0f\uff09<\/span><\/li>\n
- background (batch) \u540e\u53f0 \uff08\u6279\u5904\u7406\uff09<\/span><\/li>\n<\/ul>\n<\/li>\n
- Each queue has its own scheduling algorithm:<\/span>\n
- \n
- foreground \u2013 RR<\/span><\/li>\n
- background \u2013 FCFS<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
<\/p>\n
6.\u591a\u7ea7\u53cd\u9988\u961f\u5217 Multilevel Feedback Queue Scheduling<\/p>\n
- \n
- \u591a\u7ea7\u53cd\u9988\u961f\u5217\u7b97\u6cd5\u662f\u65f6\u95f4\u7247\u8f6e\u8f6c\u7b97\u6cd5\u548c\u4f18\u5148\u7ea7\u7b97\u6cd5\u7684\u7efc\u5408\u548c\u53d1\u5c55\u3002\u4f18\u70b9\uff1a<\/span>\n
- \n
- \u4e3a\u63d0\u9ad8\u7cfb\u7edf\u541e\u5410\u91cf\u548c\u7f29\u77ed\u5e73\u5747\u5468\u8f6c\u65f6\u95f4\u800c\u7167\u987e\u77ed\u8fdb\u7a0b<\/span><\/li>\n
- \u4e3a\u83b7\u5f97\u8f83\u597d\u7684I\/O\u8bbe\u5907\u5229\u7528\u7387\u548c\u7f29\u77ed\u54cd\u5e94\u65f6\u95f4\u800c\u7167\u987eI\/O\u578b\u8fdb\u7a0b<\/span><\/li>\n
- \u4e0d\u5fc5\u4f30\u8ba1\u8fdb\u7a0b\u7684\u6267\u884c\u65f6\u95f4\uff0c\u52a8\u6001\u8c03\u8282<\/span><\/li>\n<\/ul>\n<\/li>\n
- \u8bbe\u7f6e\u591a\u4e2a\u5c31\u7eea\u961f\u5217\uff0c\u5206\u522b\u8d4b\u4e88\u4e0d\u540c\u7684\u4f18\u5148\u7ea7\uff0c\u5982\u9010\u7ea7\u964d\u4f4e\uff0c\u961f\u52171\u7684\u4f18\u5148\u7ea7\u6700\u9ad8\u3002\u6bcf\u4e2a\u961f\u5217\u6267\u884c\u65f6\u95f4\u7247\u7684\u957f\u5ea6\u4e5f\u4e0d\u540c\uff0c\u89c4\u5b9a\u4f18\u5148\u7ea7\u8d8a\u4f4e\u5219\u65f6\u95f4\u7247\u8d8a\u957f\uff0c\u5982\u9010\u7ea7\u52a0\u500d<\/span><\/li>\n
- \u65b0\u8fdb\u7a0b\u8fdb\u5165\u5185\u5b58\u540e\uff0c\u5148\u6295\u5165\u961f\u52171\u7684\u672b\u5c3e\uff0c\u6309FCFS\u7b97\u6cd5\u8c03\u5ea6\uff1b\u82e5\u6309\u961f\u52171\u4e00\u4e2a\u65f6\u95f4\u7247\u672a\u80fd\u6267\u884c\u5b8c\uff0c\u5219\u964d\u4f4e\u6295\u5165\u5230\u961f\u52172\u7684\u672b\u5c3e\uff0c\u540c\u6837\u6309FCFS\u7b97\u6cd5\u8c03\u5ea6\uff1b\u5982\u6b64\u4e0b\u53bb\uff0c\u964d\u4f4e\u5230\u6700\u540e\u7684\u961f\u5217\uff0c\u5219\u6309”\u65f6\u95f4\u7247\u8f6e\u8f6c”\u7b97\u6cd5\u8c03\u5ea6\u76f4\u5230\u5b8c\u6210\u3002<\/span><\/li>\n
- \u4ec5\u5f53\u8f83\u9ad8\u4f18\u5148\u7ea7\u7684\u961f\u5217\u4e3a\u7a7a\uff0c\u624d\u8c03\u5ea6\u8f83\u4f4e\u4f18\u5148\u7ea7\u7684\u961f\u5217\u4e2d\u7684\u8fdb\u7a0b\u6267\u884c\u3002\u5982\u679c\u8fdb\u7a0b\u6267\u884c\u65f6\u6709\u65b0\u8fdb\u7a0b\u8fdb\u5165\u8f83\u9ad8\u4f18\u5148\u7ea7\u7684\u961f\u5217\uff0c\u5219\u62a2\u5360\u6267\u884c\u65b0\u8fdb\u7a0b\uff0c\u5e76\u628a\u88ab\u62a2\u5360\u7684\u8fdb\u7a0b\u6295\u5165\u539f\u961f\u5217\u7684\u672b\u5c3e\u3002<\/span><\/li>\n<\/ul>\n
I\/O\u578b\u8fdb\u7a0b<\/span><\/strong><\/span>\uff1a\u8ba9\u5176\u8fdb\u5165\u6700\u9ad8\u4f18\u5148\u7ea7\u961f\u5217\uff0c\u4ee5\u53ca\u65f6\u54cd\u5e94I\/O\u4ea4\u4e92\u3002\u901a\u5e38\u6267\u884c\u4e00\u4e2a\u5c0f\u65f6\u95f4\u7247\uff0c\u8981\u6c42\u53ef\u5904\u7406\u5b8c\u4e00\u6b21I\/O\u8bf7\u6c42\u7684\u6570\u636e\uff0c\u7136\u540e\u8f6c\u5165\u5230\u963b\u585e\u961f\u5217\u3002<\/span><\/p>\n
\u8ba1\u7b97\u578b\u8fdb\u7a0b<\/span><\/strong><\/span>\uff1a\u6bcf\u6b21\u90fd\u6267\u884c\u5b8c\u65f6\u95f4\u7247\uff0c\u8fdb\u5165\u66f4\u4f4e\u7ea7\u961f\u5217\u3002\u6700\u7ec8\u91c7\u7528\u6700\u5927\u65f6\u95f4\u7247\u6765\u6267\u884c\uff0c\u51cf\u5c11\u8c03\u5ea6\u6b21\u6570\u3002<\/span><\/p>\n
I\/O\u6b21\u6570\u4e0d\u591a\uff0c\u800c\u4e3b\u8981\u662fCPU\u5904\u7406\u7684\u8fdb\u7a0b\uff1a\u5728I\/O\u5b8c\u6210\u540e\uff0c\u653e\u56de\u4f18\u5148I\/O\u8bf7\u6c42\u65f6\u79bb\u5f00\u7684\u961f\u5217\uff0c\u4ee5\u514d\u6bcf\u6b21\u90fd\u56de\u5230\u6700\u9ad8\u4f18\u5148\u7ea7\u961f\u5217\u540e\u518d\u9010\u6b21\u4e0b\u964d\u3002<\/span><\/p>\n
\u4e3a\u9002\u5e94\u4e00\u4e2a\u8fdb\u7a0b\u5728\u4e0d\u540c\u65f6\u95f4\u6bb5\u7684\u8fd0\u884c\u7279\u70b9\uff0cI\/O\u5b8c\u6210\u65f6\uff0c\u63d0\u9ad8\u4f18\u5148\u7ea7\uff1b\u65f6\u95f4\u7247\u7528\u5b8c\u65f6\uff0c\u964d\u4f4e\u4f18\u5148\u7ea7\uff1b<\/span><\/p><\/blockquote>\n
Example\uff1a<\/span><\/p>\n
Q0 \u2013 time quantum 8 milliseconds<\/span><\/p>\n
Q1 \u2013 time quantum 16 milliseconds<\/span><\/p>\n
Q2 \u2013 FCFS<\/span><\/p>\n
\/\/\u5bf9\u77ed\u8fdb\u7a0b\u53cb\u597d<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"
3.\u4f18\u5148\u7ea7\u8c03\u5ea6Priority Scheduling \u8be5\u7b97\u6cd5\u603b\u662f\u628a\u5904\u7406\u673a\u5206\u914d\u7ed9\u5c31\u7eea\u961f\u5217\u4e2d\u5177\u6709\u6700\u9ad8\u4f18\u5148 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[16,20],"tags":[],"_links":{"self":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/830"}],"collection":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=830"}],"version-history":[{"count":1,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/830\/revisions"}],"predecessor-version":[{"id":842,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/830\/revisions\/842"}],"wp:attachment":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=830"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=830"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=830"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- \u4e3a\u83b7\u5f97\u8f83\u597d\u7684I\/O\u8bbe\u5907\u5229\u7528\u7387\u548c\u7f29\u77ed\u54cd\u5e94\u65f6\u95f4\u800c\u7167\u987eI\/O\u578b\u8fdb\u7a0b<\/span><\/li>\n
- \u4e3a\u63d0\u9ad8\u7cfb\u7edf\u541e\u5410\u91cf\u548c\u7f29\u77ed\u5e73\u5747\u5468\u8f6c\u65f6\u95f4\u800c\u7167\u987e\u77ed\u8fdb\u7a0b<\/span><\/li>\n
- background \u2013 FCFS<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
- background (batch) \u540e\u53f0 \uff08\u6279\u5904\u7406\uff09<\/span><\/li>\n<\/ul>\n<\/li>\n
- foreground (interactive) \u524d\u53f0\uff08\u4ea4\u4e92\u5f0f\uff09<\/span><\/li>\n
- Ready queue is partitioned into separate queues:<\/span>\n
- \u65f6\u95f4\u7247\u957f\u5ea6\u7684\u5f71\u54cd\u56e0\u7d20\uff1a\n
- \u6bcf\u6b21\u8c03\u5ea6\u65f6\u5c06CPU\u5206\u6d3e\u7ed9\u961f\u9996\u8fdb\u7a0b\uff0c\u8ba9\u5176\u6267\u884c\u4e00\u4e2a\u65f6\u95f4\u7247 (time slice) \u3002\u65f6\u95f4\u7247\u7684\u957f\u5ea6\u4ece \u51e0\u4e2ams\u5230\u51e0\u767ems\u3002<\/span><\/li>\n
- RR\u7b97\u6cd5\uff1a<\/span>\n
- \u52a8\u6001\u4f18\u5148\u6743: \u52a8\u6001\u4f18\u5148\u6743\u662f\u57fa\u4e8e\u67d0\u79cd\u539f\u5219\uff0c\u4f7f\u8fdb\u7a0b\u7684\u4f18\u5148\u6743\u968f\u65f6\u95f4\u6539\u53d8\u800c\u6539\u53d8\u3002<\/span><\/li>\n<\/ul>\n