Issue 3173: First call to winsock async connect is slow
http://code.google.com/p/chromium/issues/detail?id=3173
New issue report by [EMAIL PROTECTED]:
I have been doing some startup profiling. I found that on the first call
to ws2_32!connect(), if the socket is async, a bunch of internal work is
performed and a helper thread is spawned. The first call to connect()
takes about 6ms on my machine, all calls after are about 20x faster. One
strategy I tried was to warm up winsock by making a connect() while we are
waiting on the first dns request, avoiding a 6ms block. I verified that
ConnectEx() avoids all of this startup work, so that is probably the
correct solution.
>async_connect.exe
freq: 3579545
25630
1008
1790
844
832
#include <winsock2.h>
#include <mswsock.h>
#include <stdio.h>
void do_connect() {
SOCKET s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
unsigned long opt = 1;
ioctlsocket(s, FIONBIO, &opt);
struct sockaddr_in sa;
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = 0;
sa.sin_port = 0;
connect(s, (SOCKADDR*)&sa, sizeof(sa));
closesocket(s);
}
int main() {
WORD winsock_ver = MAKEWORD(2,2);
WSAData wsa_data;
WSAStartup(winsock_ver, &wsa_data);
LARGE_INTEGER freq, start, end;
QueryPerformanceFrequency(&freq);
printf("freq: %I64d\n", freq.QuadPart);
for (int i = 0; i < 5; ++i) {
QueryPerformanceCounter(&start);
do_connect();
QueryPerformanceCounter(&end);
printf("%I64d\n", end.QuadPart - start.QuadPart);
}
}
Issue attributes:
Status: Assigned
Owner: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED], [EMAIL PROTECTED]
Labels: Type-Bug Pri-2 OS-All Area-Misc
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