C协程实现的效率对比

前段时间实现的C协程依赖栈传递参数，在开启优化时会导致错误，于是实现了一个ucontext的版本,但ucontext的切换效率太差了，

在我的机器上执行4000W次切换需要11秒左右，这达不到我的要求，所以重新设计了实现，使得在开启优化时也能得到正确的结果.

并且效率也令人满意，4000W次切换仅需要730ms左右，足足比ucontext的实现快乐近15倍。

下面贴出实现:

#include "uthread.h"#include <stdlib.h>#include <ucontext.h>#include <pthread.h>#include "link_list.h"struct uthread{    int32_t reg[8];//0:esp,1:ebp,2:eax,3:ebx,4:ecx,5:edx,6:edi,7:esi    void *para;    uthread_t parent;    void*(*main_fun)(void*);    void *stack;    int32_t ssize;    int8_t first_run;};#ifdef _DEBUG//for debug versionvoid uthread_main_function(){    int32_t arg;     __asm__ volatile(        "movl %%eax,%0\t\n"        :        :"m"(arg)    );            uthread_t u = (uthread_t)arg;    void *ret = u->main_fun(u->para);    if(u->parent)        uthread_switch(u,u->parent,ret);    else        exit(0); }#else//for release versionvoid __attribute__((regparm(1))) uthread_main_function(void *arg){    uthread_t u = (uthread_t)arg;    void *ret = u->main_fun(u->para);    if(u->parent)        uthread_switch(u,u->parent,ret);    else        exit(0);}#endifuthread_t uthread_create(uthread_t parent,void*stack,uint32_t stack_size,void*(*fun)(void*)){    uthread_t u = (uthread_t)calloc(1,sizeof(*u));    u->parent = parent;    u->main_fun = fun;    u->stack = stack;    u->ssize = stack_size;    if(stack)    {        u->reg[0] = (int32_t)stack+stack_size-4;        u->reg[1] = (int32_t)stack+stack_size-4;    }    if(u->main_fun)        u->first_run = 1;    return u;}void uthread_destroy(uthread_t *u){    free(*u);    *u = NULL;}#ifdef _DEBUGvoid* __attribute__((regparm(3))) uthread_switch(uthread_t from,uthread_t to,void *para){    if(!from)        return NULL;    to->para = para;    int32_t esp,ebp,eax,ebx,ecx,edx,edi,esi;    //save current registers    //the order is important         __asm__ volatile(        "movl %%eax,%2\t\n"        "movl %%ebx,%3\t\n"        "movl %%ecx,%4\t\n"        "movl %%edx,%5\t\n"        "movl %%edi,%6\t\n"        "movl %%esi,%7\t\n"             "movl %%ebp,%1\t\n"        "movl %%esp,%0\t\n"        :        :"m"(esp),"m"(ebp),"m"(eax),"m"(ebx),"m"(ecx),"m"(edx),"m"(edi),"m"(esi)    );    from->reg[0] = esp;    from->reg[1] = ebp;    from->reg[2] = eax;    from->reg[3] = ebx;    from->reg[4] = ecx;    from->reg[5] = edx;    from->reg[6] = edi;    from->reg[7] = esi;        if(to->first_run)    {       to->first_run = 0;       esp = to->reg[0];       //use eax to pass arg       eax = (int32_t)to;        __asm__ volatile (            "movl %1,%%eax\t\n"            "movl %0,%%ebp\t\n"            "movl %%ebp,%%esp\t\n"            :            :"m"(esp),"m"(eax)        );              uthread_main_function();    }    else    {        esp = to->reg[0];        ebp = to->reg[1];        eax = to->reg[2];        ebx = to->reg[3];        ecx = to->reg[4];        edx = to->reg[5];        edi = to->reg[6];        esi = to->reg[7];        //the order is important        __asm__ volatile (            "movl %2,%%eax\t\n"            "movl %3,%%ebx\t\n"            "movl %4,%%ecx\t\n"            "movl %5,%%edx\t\n"            "movl %6,%%edi\t\n"            "movl %7,%%esi\t\n"                    "movl %1,%%ebp\t\n"            "movl %0,%%esp\t\n"            :            :"m"(esp),"m"(ebp),"m"(eax),"m"(ebx),"m"(ecx),"m"(edx),"m"(edi),"m"(esi)        );    }        return from->para;}#elsevoid* __attribute__((regparm(3))) uthread_switch(uthread_t from,uthread_t to,void *para){    if(!from)        return NULL;    to->para = para;    int32_t esp,ebp,edi,esi;    //save current registers    //the order is important         __asm__ volatile(        "movl %%eax,%2\t\n"        "movl %%ebx,%3\t\n"        "movl %%ecx,%4\t\n"        "movl %%edx,%5\t\n"        "movl %%edi,%6\t\n"        "movl %%esi,%7\t\n"             "movl %%ebp,%1\t\n"        "movl %%esp,%0\t\n"        :        :"m"(from->reg[0]),"m"(from->reg[1]),"m"(from->reg[2]),"m"(from->reg[3])        ,"m"(from->reg[4]),"m"(from->reg[5]),"m"(from->reg[6]),"m"(from->reg[7])    );    if(to->first_run)    {       to->first_run = 0;          //change stack       //the order is important        __asm__ volatile (            "movl %0,%%ebp\t\n"            "movl %%ebp,%%esp\t\n"            :            :"m"(to->reg[0])        );                      uthread_main_function((void*)to);    }    else    {        esp = to->reg[0];        ebp = to->reg[1];        edi = to->reg[6];        esi = to->reg[7];        //the order is important        __asm__ volatile (            "movl %2,%%eax\t\n"            "movl %3,%%ebx\t\n"            "movl %4,%%ecx\t\n"            "movl %5,%%edx\t\n"            "movl %6,%%edi\t\n"            "movl %7,%%esi\t\n"                    "movl %1,%%ebp\t\n"            "movl %0,%%esp\t\n"            :            :"m"(esp),"m"(ebp),"m"(to->reg[2]),"m"(to->reg[3])            ,"m"(to->reg[4]),"m"(to->reg[5]),"m"(edi),"m"(esi)        );    }        return from->para;}#endif

 

test.c

#include <stdio.h>#include "uthread.h"#include "SysTime.h"#include <stdlib.h>void* ufun2(void *arg){    printf("ufun2\n");    char **tmp = (char**)arg;    uthread_t self = (uthread_t)tmp[0];    uthread_t parent = (uthread_t)tmp[1];    volatile void *ptr = self;    while(ptr)    {        ptr = uthread_switch(self,parent,NULL);    }    return NULL;}char *stack1;char *stack2;void* ufun1(void *arg){    uthread_t self = (uthread_t)arg;    uthread_t u = uthread_create(self,stack2,4096,ufun2);    char* _arg[2];    _arg[0] = (char*)u;    _arg[1] = (char*)self;    int i = 0;    uint32_t tick = GetSystemMs();    for( ; i < 20000000; ++i)    {        uthread_switch(self,u,&_arg[0]);    }    printf("%d\n",GetSystemMs()-tick);    uthread_switch(self,u,NULL);    return arg;}int main(){    stack1 = (char*)malloc(4096);    stack2 = (char*)malloc(4096);    /*     * if use ucontext version    char dummy_stack[4096];    uthread_t p = uthread_create(NULL,dummy_stack,0,NULL);    */    uthread_t p = uthread_create(NULL,NULL,0,NULL);    uthread_t u = uthread_create(p,stack1,4096,ufun1);    uthread_switch(p,u,u);    printf("main end\n");    return 0;};

 

转载自：http://www.cnblogs.com/sniperHW/archive/2012/08/05/2624334.html