2 £®ÃæÏòÓû§×¼Ôò£º
1 £©Åú´¦Àíϵͳ£º
ºó±¸µÈ´ýʱ¼ä ¾Í¶ÓµÈ´ýʱ¼ä CPU Ö´ÐÐʱ¼ä ×è¶ÓµÈ´ýʱ¼ä |
×÷ÒµÖÜתʱ¼ä |
½ø³Ì ÖÜת ʱ¼ä |
ÒªÇ󯽾ù T ¡¢ W ʱ¼äҪС£¨¼´Óû§µÄÂúÒâ³Ì¶ÈÒª¸ß£©¡£
2 £©·ÖʱϵͳµÄÏìӦʱ¼ä T ¨Q 3s
3 £©ÊµÊ±ÏµÍ³±£Ö¤½ØÖ¹Ê±¼ä£¨ÈÎÎñ×î³Ù¿ªÊ¼Ê±¼ä¡¢×î³ÙÍê³Éʱ¼ä£©
4 £©ÓÅÏÈȨ׼Ôò£ºÈÃÓÅÏȼ¶¸ßµÄ½ø³ÌÓÅÏÈ»ñµÃ CPU ¡£
l µ÷¶ÈËã·¨
1. FCFS
ʵÓÃÓÚ£º×÷Òµµ÷¶È¡£µ½´ïʱ¼äÖ¸×÷Òµ½øÈëºó±¸¶ÓÁеÄʱ¼ä¡£
ʵÓÃÓÚ£º½ø³Ìµ÷¶È¡£µ½´ïʱ¼äÖ¸½ø³Ì½øÈë¾ÍÐ÷¶ÓÁеÄʱ¼ä¡£
2. SJ(p)F
ʵÓÃÓÚ£º×÷Òµµ÷¶È¡¢½ø³Ìµ÷¶È¡£
1) Óû§ÂúÒâ³Ì¶ÈºÃ
2) ³¤×÷Òµ£¨½ø³Ì£©¿ÉÄܵò»µ½ÔËÐлú»á .
3. ¼òµ¥Ê±¼äƬÂÖת·¨
1) ʱ¼äƬ q µÄÈ·¶¨ :
¹ý´óÍË»¯Îª FCFS.
¹ýС , Ò»¸öÃüÁî¶à¸öʱ¼äƬ²ÅÄÜÍê³É , ²»Âú×ãÏìӦʱ¼äÒªÇó .
2) ÏìӦʱ¼ä T ¡Ø nq n¡. Óû§ÊýÁ¿ , q¡. ϵͳ´¦ÀíÄÜÁ¦ (cpu ËÙ¶ÈµÈ ).
3) ·ÖʱϵͳÖÐ , ÒªÇó 80% ÒÔÉϵĽ»»¥ÃüÁî , ÔÚÒ»¸ö q ÖÐÍê³É , ·ñÔò T ÄÑÒÔ±£Ö¤ .
4. ÓÅÏÈȨµ÷¶ÈËã·¨
1 £©·ÇÇÀÕ¼·½Ê½£º½ø³Ì»ñµÃ CPU Ò»Ö±ÔËÐе½Íê³É£¬»òµÈ´ýʼþ²ÅÈóö CPU ¡£
2 £©ÇÀÕ¼·½Ê½£º¾ÍÐ÷¶ÓÁгöÏÖ¸ü¸ßÓÅÏȼ¶½ø³ÌÈ¥ÇÀÕ¼ÔËÐнø³ÌµÄ CPU ¡£
£³£© ¶¯Ì¬ÓÅÏȼ¶¼ÆËã
ÏßÐÔ¹æÔò£º¾ÍÐ÷¶ÓÁи÷½ø³ÌÓÅÏȼ¶ +at
ÔËÐнø³ÌÓÅÏȼ¶ +bt
a>b>0 ¿É·ÀÖ¹ÔËÐнø³Ì³¤Ê±¼äÕ¼¾Ý CPU ¡£
·ÇÏßÐÔ¹æÔò£º¾ÍÐ÷¶ÓÁУ¨ºó±¸¶ÓÁУ©µÄ½ø³Ì£¨×÷Òµ£©µÈ´ýʱ¼ä´ïij¸ø¶¨ÖµÊ±½«ÆäÓÅÏȼ¶Í»±äµ½×î´ó¡£
5£® ¶à¼¶·´À¡¶ÓÁе÷¶È£¨ÓÃÒÔ½ø³Ìµ÷¶È£© p79
£±£© ¶à¸ö¾ÍÐ÷¶ÓÁÐÓÅÏȼ¶ÒÀ´Î½µµÍ£¬·ÖµÃµÄʱ¼äƬÒÀ´ÎÔö¼Ó¡£
£²£© ͬ¶ÓÁÐÏÈÀ´ÏÈ·þÎñ¡£
£³£© ÓÅÏȵ÷¶È¸ßÓÅÏȼ¶¶ÓÁнøÔËÐÐÒ»¸öʱ¼äÅÌÆ¬£¬Ã»Íê³ÉͶÈëÏÂÒ»¸ö¾ÍÐ÷¶ÓÁС£
£´£© ½ø³ÌÊ×ÏȽøÈë×î¸ßÓÅÏȼ¶¶ÓÁС£
£µ£© ×îµÍÓÅÏȼ¶¶ÓÁнø³Ì°´Ê±¼äƬÂÖת¡£
l ËÀËø
1£® ËÀËøÔÒò
1) ×ÊÔ´²»×㣺°üÀ¨·Ç°þ¶áÐÔ×ÊÔ´ºÍÁÙʱÐÔ×ÊÔ´¡£
2) ÍÆ½øËÙ¶È·Ç·¨£ºÉú²úÕßÓëÏû·ÑÕßÎÊÌâÖÐ wait Óï¾ä¶Ôµ÷¡¢ÁÙ½çÇøÉèÖÃÓÐÎÊÌâµÈ¡£
2£® ËÀËøµÄËĸö±ØÒªÌõ¼þ
3£® ½â¾öËÀËøµÄ·½·¨
1) Ô¤·ÀËÀËø£ºÏµÍ³²»¿ÉÄÜ·¢ÉúËÀËø£¨ÆÆ»µ±ØÒªÌõ¼þÖ®Ò»£©¡£
2) ±ÜÃâËÀËø£º¿ÉÄÜ·¢ÉúËÀËø£¬Éè·¨±ÜÃâ¡£
3) ¼ì²âÓë½â³ýËÀËø
Ö÷ÒªÊÇ£ºËÀËø²úÉúÔÒò¡¢±ØÒªÌõ¼þ¡¢ÒøÐмÒËã·¨¡£
µÚ ËÄÕ ´æÖü¹ÜÀí
Ò»£®³ÌÐòµÄ×°ÈëºÍÁ´½Ó
1 Á´½Ó£º Á´½ÓÊÇÖ¸¶à¸öÄ¿±êÄ£¿éÔÚÖ´ÐÐʱµÄµØÖ·¿Õ¼ä·ÖÅäºÍÏ໥ÒýÓá£
1 £©¾²Ì¬Á´½Ó£º ¾²Ì¬Á´½ÓÊÇÔÚÉú³É¿ÉÖ´ÐÐÎļþʱ½øÐеġ£
£±£© Á´½ÓÐγÉ×°ÈëÄ£¿é£¨ÓֳƿÉÖÆÐÐÎļþ£©£¬ÓÉ×°Èë³ÌÐò×°ÈëÄÚ´æ¡£
£²£© ×°Èëʱ¶¯Ì¬Á´½Ó£º loader ±ß×°Èë±ßÁ´½Ó¡£
£³£© ÔËÐÐʱ¶¯Ì¬Á´½Ó£ºÖ÷³ÌÐòÄ£¿é×°ÈëÔËÐУ¬·¢ÉúÁËÍⲿ·ÃÎÊ£¬½øÐж¯Ì¬Á´½Ó¡£
ÔÚ×°Èë»òÔËÐÐʱ½øÐÐÁ´½Ó¡£Í¨³£±»Á´½ÓµÄ¹²Ïí´úÂë³ÆÎª¶¯Ì¬Á´½Ó¿â (DLL), »ò¹²Ïí¿â (shared library) ¡£
2. ÖØ¶¨Î»£º ÔÚ×°Èë¿ÉÖ´ÐÐÎļþʱÐèÒª½«¿ÉÖ´ÐÐÎļþÖеØÖ·£¨Ö¸ÁîºÍÊý¾Ý£©×ª±äΪÎïÀíµØÖ·µÄ¹ý³Ì¡£
