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Socket: Enable TCP_NODELAY

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DAP usually consists of small packet requests, with small packet responses. When there are many frequent, blocking requests made, Nagle's algorithm can dramatically limit the request->response rates.
This commit is contained in:
Ben Clayton 2020-03-12 17:38:45 +00:00
parent c4358807e2
commit 4dcca57756
1 changed files with 34 additions and 17 deletions
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51
src/socket.cpp
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@ -20,6 +20,7 @@
#else #else
#include <netdb.h> #include <netdb.h>
#include <netinet/in.h> #include <netinet/in.h>
#include <netinet/tcp.h>
#include <sys/select.h> #include <sys/select.h>
#include <sys/socket.h> #include <sys/socket.h>
#include <unistd.h> #include <unistd.h>
@ -74,22 +75,9 @@ class dap::Socket::Shared : public dap::ReaderWriter {
if (info) { if (info) {
auto socket = auto socket =
::socket(info->ai_family, info->ai_socktype, info->ai_protocol); ::socket(info->ai_family, info->ai_socktype, info->ai_protocol);
auto out = std::make_shared<Shared>(info, socket);
#if !defined(_WIN32) out->setOptions();
// Prevent sockets lingering after process termination, causing return out;
// reconnection issues on the same port.
int enable = 1;
setsockopt(socket, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int));
struct {
int l_onoff; /* linger active */
int l_linger; /* how many seconds to linger for */
} linger = {false, 0};
setsockopt(socket, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
#endif // !defined(_WIN32)
return std::make_shared<Shared>(info, socket);
} }
freeaddrinfo(info); freeaddrinfo(info);
@ -108,6 +96,33 @@ class dap::Socket::Shared : public dap::ReaderWriter {
SOCKET socket() { return sock.load(); } SOCKET socket() { return sock.load(); }
void setOptions() {
SOCKET s = socket();
if (s == InvalidSocket) {
return;
}
int enable = 1;
#if !defined(_WIN32)
// Prevent sockets lingering after process termination, causing
// reconnection issues on the same port.
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&enable, sizeof(enable));
struct {
int l_onoff; /* linger active */
int l_linger; /* how many seconds to linger for */
} linger = {false, 0};
setsockopt(s, SOL_SOCKET, SO_LINGER, (char*)&linger, sizeof(linger));
#endif // !defined(_WIN32)
// Enable TCP_NODELAY.
// DAP usually consists of small packet requests, with small packet
// responses. When there are many frequent, blocking requests made,
// Nagle's algorithm can dramatically limit the request->response rates.
setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (char*)&enable, sizeof(enable));
}
// dap::ReaderWriter compliance // dap::ReaderWriter compliance
bool isOpen() { bool isOpen() {
SOCKET s = socket(); SOCKET s = socket();
@ -188,7 +203,9 @@ std::shared_ptr<ReaderWriter> Socket::accept() const {
if (shared) { if (shared) {
SOCKET socket = shared->socket(); SOCKET socket = shared->socket();
if (socket != InvalidSocket) { if (socket != InvalidSocket) {
return std::make_shared<Shared>(::accept(socket, 0, 0)); auto out = std::make_shared<Shared>(::accept(socket, 0, 0));
out->setOptions();
return out;
} }
} }