Bonjour,

J'utilise la lib pthread pour découper un gros calcul en 2.
Sous windows j'obtient bien avec un bipro 30 à 40% de gain alors que sous linux je suis 10% plus lent. Je n'y comprend rien, je pensais que linux était mieux pensé que windows pour la gestion des taches !
Ou alors je m'y prend mal. Voici le code que j'utilise, il n'est pas exploitable directement mais donne une idée de la maniere don't j'ai impléménté mon calcul

Le calcul est partagé dans la fonction "myThreadEmit" nno et nn1 valent respectivement (0->50000) & (50000->100000) pour les thread 1 & 2

"emit_partielle_c" est la fonction que je chronometre

Si quelqu'un voit un loup, merci d'avance

Code : Sélectionner tout - Visualiser dans une fenêtre à part
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
 
struct dataEmit {
  long nn0,nn1,iptsss;
  double *cord,*loss,
    xm,ym,xpm,ypm,em,pm,pzm,erest,wavel,radian,wsync,
    dpm,zdpm,dp2,z2,z4,dp4,z2dp2,dp3z,x2,y2,xp2,
    yp2,xxpm,yypm,xym,xpypm,xypm,x4,y4,xp4,x2xp2,
    y2yp2,x3xp,xp3x,yp3y,xmax,ymax,r2,rp2,rrrp,
    z3dp,xpym,yp4,y3yp,zm;
} my_structEmit;
 
 
 
void *myThreadEmit(void *arg)
{
  double un_s_erest,gm,xx,yy,xxp,yyp,pp,ee,rr,rrp,bg;
  double sqrtxy,pzi,bz,ddp,zz,ddp2;
  double xx2,yy2,xxp2,yyp2,zz2,kwavel,un_s_c,un_s_pzm;
  int np;
 
  struct dataEmit *d;
  d = (struct dataEmit *)arg;
 
  un_s_erest=1./ d->erest;
  kwavel=d->wavel/360.;
  un_s_c=1./299792458.;
  un_s_pzm=1./ d->pzm;
 
 
  for (np=d->nn0;np<d->nn1;np++) {
    if (d->loss[np]==0) {
      gm = 1+d->cord[np*6+5]*un_s_erest;
      if (gm>1.) {
        xx = d->cord[np*6];
        yy = d->cord[np*6+2];
        xxp = d->cord[np*6+1];
        yyp = d->cord[np*6+3];
        pp = d->cord[np*6+4]/ d->radian;
        ee = d->cord[np*6+5]- d->wsync;
 
        rr = sqrt(xx*xx+yy*yy);
        if (rr!=0) rrp = (xx*xxp+yy*yyp)/rr; else rrp=0;
        d->r2+=rr*rr;
        d->rp2+=rrp*rrp;
        d->rrrp+=rr*rrp;
 
        if (fabs(xx)>d->xmax) d->xmax=fabs(xx);
        if (fabs(yy)>d->ymax) d->ymax=fabs(yy);
 
        xx-=d->xm;
        yy-=d->ym;
        xxp-=d->xpm;
        yyp-=d->ypm;
        pp-=d->pm;
        ee-=d->em;
 
        xx2=xx*xx;
        xxp2=xxp*xxp;
        yy2=yy*yy;
        yyp2=yyp*yyp;
 
        bg = sqrt(gm*gm-1);
        sqrtxy = 1./sqrt(1+xxp2+yyp2);
        pzi=bg* d->erest*un_s_c*sqrtxy;
        bz = bg*sqrtxy/gm;
        ddp=un_s_pzm*pzi-1;
        zz=-pp*bz*kwavel;
 
        d->dpm+=ddp;
        d->zm+=zz;
        d->zdpm+=ddp*zz;
        ddp2=ddp*ddp;
        zz2=zz*zz;
        d->dp2+=ddp2;
        d->z2+=zz2;
        d->z4+=zz2*zz2;
        d->dp4+=ddp2*ddp2;
        d->z2dp2+=zz2*ddp2;
        d->z3dp+=zz*zz2*ddp;
        d->dp3z+=ddp*ddp2*zz;
 
        d->x2+=xx2;
        d->y2+=yy2;
        d->xp2+=xxp2;
        d->yp2+=yyp2;
 
        d->xxpm+=xx*xxp;
        d->yypm+=yy*yyp;
        d->xym+=xx*yy;
        d->xpypm+=xxp*yyp;
        d->xypm+=xx*yyp;
        d->xpym+=xxp*yy;
 
        d->x4+=xx2*xx2;
        d->y4+=yy2*yy2;
        d->xp4+=xxp2*xxp2;
        d->yp4+=yyp2*yyp2;
        d->x2xp2+=xx2*xxp2;
        d->y2yp2+=yy2*yyp2;
        d->x3xp+=xx*xx2*xxp;
        d->xp3x+=xxp*xxp2*xx;
        d->y3yp+=yy*yy2*yyp;
        d->yp3y+=yyp*yyp2*yy;
      }
    }
  }
  pthread_exit(NULL);
  return(NULL);
}
 
 
void emit_partielle_c_(int *npoint,double *cord,double *loss,
  double *xm,double *ym,double *xpm,double *ypm,double *em,double *pm,double *pzm,double *erest,double *wavel,double *radian,double *wsync,
  double *dpm,double *zdpm,double *dp2,double *z2,double *z4,
  double *dp4,double *z2dp2,double *dp3z,double *x2,double *y2,double *xp2,
  double *yp2,double *xxpm,double *yypm,double *xym,double *xpypm,
  double *xypm,double *x4,double *y4,double *xp4,double *x2xp2,
  double *y2yp2,double *x3xp,double *xp3x,double *yp3y,
  double *xmax,double *ymax,double *r2,double *rp2,double *rrrp,
  double *z3dp,double *xpym,double *yp4,double *y3yp,double *zm)
{
  long nn0,nn1;
  int i,rc,Nthr=nbr_thread_partran;
  pthread_t tid[Nthr];
  struct dataEmit d[Nthr];
 
 
  for (i=0;i<Nthr;i++) {
    nn0=i*(*npoint)/Nthr;
    nn1=(i+1)*(*npoint)/Nthr;
    if (i==Nthr-1) nn1=*npoint;
    d[i].nn0=nn0;
    d[i].nn1=nn1;
    d[i].iptsss=*npoint;
    d[i].cord=cord;
    d[i].loss=loss;
    d[i].xm=*xm;
    d[i].ym=*ym;
    d[i].xpm=*xpm;
    d[i].ypm=*ypm;
    d[i].em=*em;
    d[i].pm=*pm;
    d[i].pzm=*pzm;
    d[i].erest=*erest;
    d[i].wavel=*wavel;
    d[i].radian=*radian;
    d[i].wsync=*wsync;
    d[i].dpm=d[i].zdpm=d[i].dp2=d[i].z2=d[i].z4=d[i].dp4=d[i].z2dp2=0;
    d[i].dp3z=d[i].x2=d[i].y2=d[i].xp2=d[i].yp2=d[i].xxpm=d[i].yypm=0;
    d[i].xym=d[i].xpypm=d[i].xypm=d[i].x4=d[i].y4=d[i].xp4=d[i].x2xp2=0;
    d[i].y2yp2=d[i].x3xp=d[i].xp3x=d[i].yp3y=d[i].xmax=d[i].ymax=0;
    d[i].r2=d[i].rp2=d[i].rrrp=d[i].z3dp=d[i].xpym=d[i].yp4=d[i].y3yp=d[i].zm=0;
  }
 
  for (i=0;i<Nthr;i++) {
    rc=pthread_create(&tid[i],NULL, myThreadEmit, (void *)&d[i]);
    if (rc) {
      printf("ERROR: return code from pthread_create() is %d\n",rc);
    }
  }
 
  for(i=0; i<Nthr; i++) {
    rc = pthread_join(tid[i],NULL);
    if (rc) {
      printf("ERROR: return code from pthread_join() is %d\n",rc);
    }
  }
 
  for (i=0;i<Nthr;i++) {
    *r2=*r2+d[i].r2;
    *rp2=*rp2+d[i].rp2;
    *rrrp=*rrrp+d[i].rrrp;
    *x2=*x2+d[i].x2;
    *y2=*y2+d[i].y2;
    *xp2=*xp2+d[i].xp2;
    *yp2=*yp2+d[i].yp2;
    *xxpm=*xxpm+d[i].xxpm;
    *yypm=*yypm+d[i].yypm;
    *xym=*xym+d[i].xym;
    *xpypm=*xpypm+d[i].xpypm;
    *xypm=*xypm+d[i].xypm;
    *xpym=*xpym+d[i].xpym;
    *x4=*x4+d[i].x4;
    *y4=*y4+d[i].y4;
    *xp4=*xp4+d[i].xp4;
    *yp4=*yp4+d[i].yp4;
    *x2xp2=*x2xp2+d[i].x2xp2;
    *y2yp2=*y2yp2+d[i].y2yp2;
    *x3xp=*x3xp+d[i].x3xp;
    *xp3x=*xp3x+d[i].xp3x;
    *y3yp=*y3yp+d[i].y3yp;
    *yp3y=*yp3y+d[i].yp3y;
    *dpm=*dpm+d[i].dpm;
    *zm=*zm+d[i].zm;
    *zdpm=*zdpm+d[i].zdpm;
    *dp2=*dp2+d[i].dp2;
    *z2=*z2+d[i].z2;
    *z4=*z4+d[i].z4;
    *dp4=*dp4+d[i].dp4;
    *z2dp2=*z2dp2+d[i].z2dp2;
    *z3dp=*z3dp+d[i].z3dp;
    *dp3z=*dp3z+d[i].dp3z;
    if (d[i].xmax>*xmax) *xmax=d[i].xmax;
    if (d[i].ymax>*ymax) *ymax=d[i].ymax;
  }
}