PageReplacement_1.cpp_操作系统_页置换_

/* FIFO algorithm run command: ./PageReplacement input.txt 4096 3 FIFO The first parameter specifies the input file name as input.txt, the second parameter specifies the page size to be 4096, the third parameter specifies the number of pages to be 3, and the fourth parameter specifies the use of the FIFO algorithm. ./PageReplacement input.txt 4096 3 LRU The first parameter specifies the input file name as input.txt, the second parameter specifies the page size to be 4096, the third parameter specifies the number of pages to be 3, and the fourth parameter specifies the LRU algorithm. ./PageReplacement input.txt 4096 3 ARB 4 3 The first parameter specifies the input file name is input.txt, the second parameter specifies the page size to be 4096, the third parameter specifies the number of pages to be 3, the fourth parameter specifies the use of the ARB algorithm, and the fifth parameter specifies Number of register bits, the sixth parameter specifies the shift register refresh frequency bit 3 ./PageReplacement input.txt 4096 3 WSARB 4 3 3 The first parameter specifies the input file name is input.txt, the second parameter specifies the page size to be 4096, the third parameter specifies the number of pages to be 3, the fourth parameter specifies the WSARB algorithm, and the fifth parameter specifies The number of register bits, the sixth parameter specifies the shift register refresh frequency bit 3, and the seventh parameter specifies the window to be 3 */ #include <iostream> #include <vector> #include <string> #include <string.h> #include <fstream> using namespace std; int events=0; int reads=0; int writes=0; int faults=0; struct Frame { long long num; bool dirty; unsigned char re; unsigned char cnt; Frame(long long n=-1,bool d=false,unsigned char r=0,unsigned char c=0) { num=n; dirty=d; re=r; cnt=c; } }; void PageFIFO(vector<Frame> &frames,long long framenum,bool write) { int i; // Traversing the page in the current dynamic array to find out if the currently accessed page is inside for(i=0;i<frames.size();i++) { // Find the page you are currently visiting if(frames[i].num==framenum) { // To write, mark the current page as dirty page if(write==true) frames[i].dirty=write; break; } } // If i is greater than or equal to the size of the page, the page to be accessed is not in memory, and page replacement is required. if(i>=frames.size()) { // Write a disk if it is dirty if(frames[0].dirty) writes++; // Delete the first page you entered and add the new page to the end frames.erase(frames.begin()); frames.push_back(Frame(framenum,write)); reads++; faults++; } events++; } // LUR algorithm void PageLRU(vector<Frame> &frames,long long framenum,bool write) { int i; // Traversing the page in the current dynamic array to find out if the currently accessed page is inside for(i=0;i<frames.size();i++) { // Find the page that is currently visiting if(frames[i].num==framenum) { // Write a disk if it is dirty if(write==true) frames[i].dirty=write; if(i<frames.size()-1) { // Move the current page to the end Frame f=frames[i]; frames.erase(frames.begin()+i); frames.push_back(f); } break; } } // If i is greater than or equal to the size of the page, the page to be accessed is not in memory, and page replacement is required. if(i>=frames.size()) { // Write a disk if it is dirty if(frames[0].dirty) writes++; // Move the current page to the end frames.erase(frames.begin()); frames.push_back(Frame(framenum,write)); reads++; faults++; } events++; } // ARB algorithm: void PageARB(vector<Frame> &frames,long long framenum,bool write,int bit,int interval) { int i; // Judging that the refresh time has arrived if(events%interval==0) { // All pages are traversed and the shift register is shifted one bit to the right for(i=0;i<frames.size();i++) frames[i].re>>=1; } // Iterates through the current dynamic array to see if the currently accessed page is in it for(i=0;i<frames.size();i++) { // Find the currently accessed page if(frames[i].num==framenum) { // Write a disk if it is dirty if(write==true) frames[i].dirty=write; // Update the register to the highest bit of 1 frames[i].re|=1<<(bit-1); break; } } // If I is larger than or equal to the size of the page, // the current page to be accessed is not in memory and a page replacement is required if(i>=frames.size()) { int minindex=0; // Traverse the current page to find the item with the smallest register value for(i=0;i<frames.size();i++) { if(frames[minindex].re>frames[i].re) minindex=i; } // Determine if it is a dirty page and write to disk if(frames[minindex].dirty) writes++; // Delete the item with the smallest register value, eliminate it, and add the new page to the end frames.erase(frames.begin()+minindex); frames.push_back(Frame(framenum,write,1<<(bit-1))); reads++; faults++; } events++; } // WSARB algorithm: void PageWSARB(vector<Frame> &frames,long long framenum,bool write,int bit,int interval,int window) { int i; // Determine if the refresh time is up if(events%interval==0) { // All pages are traversed and the shift register is shifted one bit to the right for(i=0;i<frames.size();i++) frames[i].re>>=1; } // Iterate through the page, updating the window value -1 for(i=0;i<frames.size();i++) { if(frames[i].cnt>0) frames[i].cnt-=1; } // Iterates through the current dynamic array to see if the currently accessed page is in it for(i=0;i<frames.size();i++) { // Find the currently accessed page if(frames[i].num==framenum) { // Write a disk if it is dirty if(write==true) frames[i].dirty=write; // The update register value has a maximum value of 1, and the update window value has a maximum value frames[i].re|=1<<(bit-1); frames[i].cnt=window; break; } } // If I is larger than or equal to the size of the page, the current page to be accessed is not in memory and a page replacement is required if(i>=frames.size()) { int minindex=0; // Traverse the current page to find the item with the smallest window value for(i=0;i<frames.size();i++) { if(frames[minindex].cnt>frames[i].cnt) minindex=i; } // Traverse the current page to find the item with the smallest register value in the same case as the window minimum for(i=minindex;i<frames.size();i++) { if(frames[minindex].cnt!=frames[i].cnt) continue; if(frames[minindex].re>frames[i].re) minindex=i; }