在写c/c++时如何降低cpu使用率

wgf3341869 2013-08-21 05:02:25

我写了一个程序C/C++程序，单线程运行时没有问题，当多线程并发运行时发现cpu很快就满了，也不知道原因是什么，不知道怎么改代码，各位高手给点意见，是不是需要贴代码上去才能看清楚。

...全文

977 11 打赏收藏转发到动态举报

写回复

用AI写文章

11 条回复

切换为时间正序

请发表友善的回复…

发表回复

东莞某某某 2013-08-27

打赏
举报

是不是死循环不行的话是不是要计算占用CPU时间来锁定

wgf3341869 2013-08-27

打赏
举报

至于src的数据是用opencv读取的，目前主要是jpeg，即是调用函数IplImage *src = cvLoadImage(filename,-1);

wgf3341869 2013-08-27

打赏
举报

int inter_linear_jpeg(IplImage *src,IplImage *dst,char *outputfilename,int quality){ if(src==NULL){ printf("can not open source file!"); return -1; } FILE *outfile; if((outfile = fopen(outputfilename,"wb"))==NULL){ printf( "can not open file to output %s/n", outputfilename); return -1; } //variable for jpeg start--------------- struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; int row_stride; /* physical row width in image buffer */ JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */ cinfo.err = jpeg_std_error(&jerr); jpeg_create_compress(&cinfo); jpeg_stdio_dest(&cinfo, outfile); cinfo.image_width = dst->width; /* image width and height, in pixels */ cinfo.image_height = dst->height; cinfo.input_components = dst->nChannels; /* # of color components per pixel */ /* colorspace of input image */ if(dst->nChannels==3) cinfo.in_color_space = JCS_RGB; else cinfo.in_color_space =JCS_GRAYSCALE; jpeg_set_defaults(&cinfo); jpeg_set_quality(&cinfo, quality, TRUE); jpeg_start_compress(&cinfo, TRUE); //variable for jpeg end--------------- //variable for inter_linear start------------- int i,j,k,chanel=src->nChannels,t; int si,sj,si1,sj1; double wk=(double)(src->width)/dst->width,hk=(double)(src->height)/dst->height; double u,v,th,tw; uchar* pst=(uchar*)dst->imageData; uchar* prc=(uchar*)src->imageData; //variable for inter_linear end------------------ //scaling and compressing for(i=th=0;i<dst->height;i++){ si=(int)th; si1=min(si+1,src->height-1); u=th-si; for(j=tw=t=0;j<dst->width;j++){ sj=(int)tw; sj1=min(sj+1,src->width-1); v=tw-sj; int ij=src->widthStep*si+sj*chanel,i1j=src->widthStep*si1+sj*chanel,ij1=src->widthStep*si+sj1*chanel,i1j1=src->widthStep*si1+sj1*chanel; for(k=0;k<chanel;k++){ pst[t+chanel-k-1]=(uchar)(prc[ij+k]+u*(prc[ij1+k]-prc[ij+k])+v*(prc[i1j+k]-prc[ij+k])+u*v*(prc[ij+k]-prc[i1j+k]-prc[ij1+k]+prc[i1j1+k])); } tw+=wk; t+=chanel; } row_pointer[0]=(unsigned char*)pst; (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); pst=(uchar*)(pst+dst->widthStep); th+=hk; } //release jpeg_finish_compress(&cinfo); fclose(outfile); jpeg_destroy_compress(&cinfo); return 1; }

wgf3341869 2013-08-27