By the way I use hiperfifo.c to send HTTPS 40 requests at the same time in
https://curl.haxx.se/libcurl/c/hiperfifo.html
CPU sometimes burst to 69% or 80%, quickly down to 25% then to 0.0%
Code below:
static void fifo_cb(int fd, short event, void *arg)
{
char s[1024];
long int rv=0;
int n=0;
GlobalInfo *g = (GlobalInfo *)arg;
(void)fd; /* unused */
(void)event; /* unused */
int i=0;
do {
s[0]='\0';
rv=fscanf(g->input, "%1023s%n", s, &n);
s[n]='\0';
if(n && s[0]) {
for(i=0; i<40; i++) {
//printf("new_conn start\n");
new_conn("https://test.example.com";, arg); //This code I add
}
}
else
break;
} while(rv != EOF);
}
Complete code see attachment.
On Thu, Aug 10, 2017 at 9:23 AM, Jack <[email protected]> wrote:
>
>
> On Thu, Aug 10, 2017 at 6:33 AM, Daniel Stenberg <[email protected]> wrote:
>
>> On Wed, 9 Aug 2017, fan fan via curl-library wrote:
>>
>> In my application, I using libcurl to send 40 HTTP requests in every
>>> one second. As I test, this consume much CPU, my application such as:
>>>
>>> main thread for sending request and using epoll listen fds whether read
>>> or write.
>>>
>>> while(running) {
>>> int ret = epoll_wait(epollFd, events, maxEventNum, 10); //10ms
>>>
>>
>> Unconditionally returning every 10 milliseconds like this will make you
>> spend a lot of CPU in vein. Don't do that. libcurl tells you how long it
>> wants you to wait at most. No need to spin around a lap when there's
>> nothing for libcurl to do.
>>
>> Do you also call libcurl to tell there's a timeout if the 10 milliseconds
>> lapse or when do you do that?
>
>
> [Fan] Maybe this is not root cause, because when no http request send,
> CPU almost 0.1%. of course I need to expand waiting time.
> this epoll_wait for listening every easy handle fd, I
> set CURLMOPT_SOCKETFUNCTION, when callback, I add this fd to epoll events.
> of course I set CURLMOPT_TIMERFUNCTION, when timeout, I call
> curl_multi_socket_action
> again.
>
>>
>>
>> for (i = 0; i < ret; i++) {
>>> if (events[i].events & EPOLLIN) {
>>> curl_multi_socket_action // set CURL_CSELECT_IN
>>> curl_multi_info_read // for reading
>>>
>>
>> I think you should put the curl_multi_info_read() call outside of the
>> loop checking for activities, since it might not have anything to return
>> and then its a bit of a waste to call it up to 40 times.
>>
>> But sure, curl_multi_socket_action() may of course consume CPU since
>> that's the function that will handle the traffic on the socket you give it
>> (and possibly on a few others if necessary).
>
>
> [Fan] So, when do I call curl_multi_info_read?
> I refer to:
> https://curl.haxx.se/libcurl/c/hiperfifo.html
> when socket have something to read, call curl_multi_info_read,
> is it correct?
>
>>
>>
>> As I test, send 100 or 200 or 300 or 400 or 500 in parallel maybe
>>> consume
>>> cpu 100%.
>>>
>>
>> On modern hardware that shouldn't happen.
>
> [Fan] Agree
>
>>
>>
>> I found there are too much EPOLLIN event, this consume much cpu.
>>>
>>
>> What do you mean with too much EPOLLIN event? If libcurl tells you to
>> wait for that, shouldn't you then be glad you get it so that you can
>> download the data?
>
>
> [Fan] I add socket fd to epoll event when CURLMOPT_SOCKETFUNCTION
> callback.
> If there has a lot of easy handle in processing, trigger
> frequently.
> CURLMOPT_TIMERFUNCTION not about epoll fd, is it right?
> CURLMOPT_TIMERFUNCTION only indicating whether time out or
> not.
>
>>
>>
>> 1. Does my use libcurl wrong?
>>>
>>
>> Ineffective at least. But you also didn't show the whole program so its
>> not possible to tell the whole story.
>
> [Fan] Agree
>
>>
>>
>> 2. Have any performance measurement for libcurl process in parallel?
>>>
>>
>> It should easily handle thousands of parallel connections, CPU wise. Very
>> likely tens of thousands too. Of course they may have to struggle with each
>> other for other resources (like bandwidth).
>
> [Fan]Awesome
>
>>
>>
>> --
>>
>> / daniel.haxx.se
>>
>
>
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2016, Daniel Stenberg, <[email protected]>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
/* <DESC>
* multi socket API usage with libevent 2
* </DESC>
*/
/* Example application source code using the multi socket interface to
download many files at once.
Written by Jeff Pohlmeyer
Requires libevent version 2 and a (POSIX?) system that has mkfifo().
This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
sample programs.
When running, the program creates the named pipe "hiper.fifo"
Whenever there is input into the fifo, the program reads the input as a list
of URL's and creates some new easy handles to fetch each URL via the
curl_multi "hiper" API.
Thus, you can try a single URL:
% echo http://www.yahoo.com > hiper.fifo
Or a whole bunch of them:
% cat my-url-list > hiper.fifo
The fifo buffer is handled almost instantly, so you can even add more URL's
while the previous requests are still being downloaded.
Note:
For the sake of simplicity, URL length is limited to 1023 char's !
This is purely a demo app, all retrieved data is simply discarded by the write
callback.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include <sys/poll.h>
#include <curl/curl.h>
#include <event2/event.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
int doneNum = 0;
/* Global information, common to all connections */
typedef struct _GlobalInfo
{
struct event_base *evbase;
struct event *fifo_event;
struct event *timer_event;
CURLM *multi;
int still_running;
FILE* input;
} GlobalInfo;
/* Information associated with a specific easy handle */
typedef struct _ConnInfo
{
CURL *easy;
char *url;
GlobalInfo *global;
char error[CURL_ERROR_SIZE];
char content[4096];
int len;
int fan;
struct curl_slist *headers;
} ConnInfo;
/* Information associated with a specific socket */
typedef struct _SockInfo
{
curl_socket_t sockfd;
CURL *easy;
int action;
long timeout;
struct event *ev;
int evset;
GlobalInfo *global;
} SockInfo;
/* Update the event timer after curl_multi library calls */
static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g)
{
struct timeval timeout;
(void)multi; /* unused */
timeout.tv_sec = timeout_ms/1000;
timeout.tv_usec = (timeout_ms%1000)*1000;
evtimer_add(g->timer_event, &timeout);
return 0;
}
/* Die if we get a bad CURLMcode somewhere */
static void mcode_or_die(const char *where, CURLMcode code)
{
if(CURLM_OK != code) {
const char *s;
switch (code) {
case CURLM_BAD_HANDLE: s="CURLM_BAD_HANDLE"; break;
case CURLM_BAD_EASY_HANDLE: s="CURLM_BAD_EASY_HANDLE"; break;
case CURLM_OUT_OF_MEMORY: s="CURLM_OUT_OF_MEMORY"; break;
case CURLM_INTERNAL_ERROR: s="CURLM_INTERNAL_ERROR"; break;
case CURLM_UNKNOWN_OPTION: s="CURLM_UNKNOWN_OPTION"; break;
case CURLM_LAST: s="CURLM_LAST"; break;
default: s="CURLM_unknown";
break;
case CURLM_BAD_SOCKET: s="CURLM_BAD_SOCKET";
//fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
/* ignore this error */
return;
}
//fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
exit(code);
}
}
/* Check for completed transfers, and remove their easy handles */
static void check_multi_info(GlobalInfo *g)
{
char *eff_url;
CURLMsg *msg;
int msgs_left;
ConnInfo *conn;
CURL *easy;
CURLcode res;
//fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
if(msg->msg == CURLMSG_DONE) {
easy = msg->easy_handle;
res = msg->data.result;
curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
//fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
fprintf(MSG_OUT, "DONE num=%d\n", doneNum++);
curl_multi_remove_handle(g->multi, easy);
free(conn->url);
curl_easy_cleanup(easy);
free(conn);
}
}
}
/* Called by libevent when we get action on a multi socket */
static void event_cb(int fd, short kind, void *userp)
{
GlobalInfo *g = (GlobalInfo*) userp;
CURLMcode rc;
int action =
(kind & EV_READ ? CURL_CSELECT_IN : 0) |
(kind & EV_WRITE ? CURL_CSELECT_OUT : 0);
rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
mcode_or_die("event_cb: curl_multi_socket_action", rc);
check_multi_info(g);
if(g->still_running <= 0) {
//fprintf(MSG_OUT, "last transfer done, kill timeout\n");
if(evtimer_pending(g->timer_event, NULL)) {
evtimer_del(g->timer_event);
}
}
}
/* Called by libevent when our timeout expires */
static void timer_cb(int fd, short kind, void *userp)
{
GlobalInfo *g = (GlobalInfo *)userp;
CURLMcode rc;
(void)fd;
(void)kind;
rc = curl_multi_socket_action(g->multi,
CURL_SOCKET_TIMEOUT, 0, &g->still_running);
mcode_or_die("timer_cb: curl_multi_socket_action", rc);
check_multi_info(g);
}
/* Clean up the SockInfo structure */
static void remsock(SockInfo *f)
{
if(f) {
if(f->evset)
event_free(f->ev);
free(f);
}
}
/* Assign information to a SockInfo structure */
static void setsock(SockInfo*f, curl_socket_t s, CURL*e, int act, GlobalInfo*g)
{
int kind =
(act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST;
f->sockfd = s;
f->action = act;
f->easy = e;
if(f->evset)
event_free(f->ev);
f->ev = event_new(g->evbase, f->sockfd, kind, event_cb, g);
f->evset = 1;
event_add(f->ev, NULL);
}
/* Initialize a new SockInfo structure */
static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
{
SockInfo *fdp = calloc(sizeof(SockInfo), 1);
fdp->global = g;
setsock(fdp, s, easy, action, g);
curl_multi_assign(g->multi, s, fdp);
}
/* CURLMOPT_SOCKETFUNCTION */
static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
{
GlobalInfo *g = (GlobalInfo*) cbp;
SockInfo *fdp = (SockInfo*) sockp;
const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
//fprintf(MSG_OUT,
// "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
if(what == CURL_POLL_REMOVE) {
//fprintf(MSG_OUT, "\n");
remsock(fdp);
}
else {
if(!fdp) {
//fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
addsock(s, e, what, g);
}
else {
//fprintf(MSG_OUT,
// "Changing action from %s to %s\n",
// whatstr[fdp->action], whatstr[what]);
setsock(fdp, s, e, what, g);
}
}
return 0;
}
/* CURLOPT_WRITEFUNCTION */
static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
{
size_t realsize = size * nmemb;
ConnInfo *conn = (ConnInfo*) data;
//(void)ptr;
//(void)conn;
//printf("\n\nfan=%d\n", conn->fan);
memcpy(conn->content+conn->len, ptr, realsize);
conn->len += realsize;
//printf("\n\ncontent=%s\n\n", conn->content);
if(conn->fan == 0)
conn->fan++;
return realsize;
}
/* CURLOPT_PROGRESSFUNCTION */
static int prog_cb (void *p, double dltotal, double dlnow, double ult,
double uln)
{
ConnInfo *conn = (ConnInfo *)p;
(void)ult;
(void)uln;
//fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
return 0;
}
/* Create a new easy handle, and add it to the global curl_multi */
static void new_conn(char *url, GlobalInfo *g)
{
ConnInfo *conn;
CURLMcode rc;
conn = calloc(1, sizeof(ConnInfo));
memset(conn, 0, sizeof(ConnInfo));
conn->error[0]='\0';
conn->easy = curl_easy_init();
if(!conn->easy) {
//fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
exit(2);
}
#if 0
conn->global = g;
conn->url = strdup(url);
curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
fprintf(MSG_OUT,
"Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
rc = curl_multi_add_handle(g->multi, conn->easy);
mcode_or_die("new_conn: curl_multi_add_handle", rc);
#endif
//Set method
curl_easy_setopt(conn->easy, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
conn->global = g;
conn->url = strdup(url);
//Set header
//struct curl_slist *headers = NULL;
conn->headers = curl_slist_append(conn->headers, "Accept:application/json;charset=UTF-8");
conn->headers = curl_slist_append(conn->headers, "Content-Type:application/json; charset=UTF-8");
conn->headers = curl_slist_append(conn->headers, "Expect:");
curl_easy_setopt(conn->easy, CURLOPT_HTTPHEADER, conn->headers);
//Set body
char *body = "test";
curl_easy_setopt(conn->easy, CURLOPT_POSTFIELDS, body);
curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(conn->easy, CURLOPT_HEADER, 1L);
curl_easy_setopt(conn->easy, CURLOPT_NOSIGNAL, 1L);
curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1);
curl_easy_setopt(conn->easy, CURLOPT_FORBID_REUSE, 1);
curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 0);
curl_easy_setopt(conn->easy, CURLOPT_TCP_NODELAY, 1L);
//curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
//curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
rc = curl_multi_add_handle(g->multi, conn->easy);
//mcode_or_die("new_conn: curl_multi_add_handle", rc);
/* note that the add_handle() will set a time-out to trigger very soon so
that the necessary socket_action() call will be called by this app */
}
/* This gets called whenever data is received from the fifo */
static void fifo_cb(int fd, short event, void *arg)
{
char s[1024];
long int rv=0;
int n=0;
GlobalInfo *g = (GlobalInfo *)arg;
(void)fd; /* unused */
(void)event; /* unused */
int i=0;
do {
s[0]='\0';
rv=fscanf(g->input, "%1023s%n", s, &n);
s[n]='\0';
if(n && s[0]) {
for(i=0; i<40; i++) {
//printf("new_conn start\n");
new_conn("https://test.example.com";, arg);
}
}
else
break;
} while(rv != EOF);
}
/* Create a named pipe and tell libevent to monitor it */
static const char *fifo = "hiper.fifo";
static int init_fifo (GlobalInfo *g)
{
struct stat st;
curl_socket_t sockfd;
//fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
if(lstat (fifo, &st) == 0) {
if((st.st_mode & S_IFMT) == S_IFREG) {
errno = EEXIST;
perror("lstat");
exit (1);
}
}
unlink(fifo);
if(mkfifo (fifo, 0600) == -1) {
perror("mkfifo");
exit (1);
}
sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
if(sockfd == -1) {
perror("open");
exit (1);
}
g->input = fdopen(sockfd, "r");
//fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
g->fifo_event = event_new(g->evbase, sockfd, EV_READ|EV_PERSIST, fifo_cb, g);
event_add(g->fifo_event, NULL);
return (0);
}
static void clean_fifo(GlobalInfo *g)
{
event_free(g->fifo_event);
fclose(g->input);
unlink(fifo);
}
int main(int argc, char **argv)
{
GlobalInfo g;
(void)argc;
(void)argv;
memset(&g, 0, sizeof(GlobalInfo));
g.evbase = event_base_new();
init_fifo(&g);
g.multi = curl_multi_init();
g.timer_event = evtimer_new(g.evbase, timer_cb, &g);
/* setup the generic multi interface options we want */
curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
/* we don't call any curl_multi_socket*() function yet as we have no handles
added! */
event_base_dispatch(g.evbase);
/* this, of course, won't get called since only way to stop this program is
via ctrl-C, but it is here to show how cleanup /would/ be done. */
clean_fifo(&g);
event_free(g.timer_event);
event_base_free(g.evbase);
curl_multi_cleanup(g.multi);
return 0;
}
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