Changeset bb58825

Timestamp:

Jan 14, 2021, 12:45:28 PM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

b0f6190a

Parents:

a00bc5b

Message:

io_uring_register is so debilitatingly slow on some machines I have to hard block preemption.

Location:

libcfa/src/concurrency

Files:

• io/setup.cfa (modified) (2 diffs)
• preemption.cfa (modified) (2 diffs)

libcfa/src/concurrency/io/setup.cfa

@@ -314 +314 @@
         }
 
+        extern void signal_block( int sig );
+        extern void signal_unblock( int sig );
+
         static void __io_create( __io_data & this, const io_context_params & params_in ) {
                 // Step 1 : call to setup
@@ -430 +433 @@
 
                 // Step 4 : eventfd
-                int efd;
-                for() {
-                        efd = eventfd(0, 0);
-                        if (efd < 0) {
-                                if (errno == EINTR) continue;
-                                abort("KERNEL ERROR: IO_URING EVENTFD - %s\n", strerror(errno));
-                        }
-                        break;
-                }
-
-                int ret;
-                for() {
-                        ret = syscall( __NR_io_uring_register, fd, IORING_REGISTER_EVENTFD, &efd, 1);
-                        if (ret < 0) {
-                                if (errno == EINTR) continue;
-                                abort("KERNEL ERROR: IO_URING EVENTFD REGISTER - %s\n", strerror(errno));
-                        }
-                        break;
-                }
+                // io_uring_register is so f*cking slow on some machine that it
+                // will never succeed if preemption isn't hard blocked
+                signal_block( SIGUSR1 );
+
+                int efd = eventfd(0, 0);
+                if (efd < 0) {
+                        abort("KERNEL ERROR: IO_URING EVENTFD - %s\n", strerror(errno));
+                }
+
+                int ret = syscall( __NR_io_uring_register, fd, IORING_REGISTER_EVENTFD, &efd, 1);
+                if (ret < 0) {
+                        abort("KERNEL ERROR: IO_URING EVENTFD REGISTER - %s\n", strerror(errno));
+                }
+
+                signal_unblock( SIGUSR1 );
 
                 // some paranoid checks

libcfa/src/concurrency/preemption.cfa

@@ -394 +394 @@
 
 // sigprocmask wrapper : unblock a single signal
-static inline void signal_unblock( int sig ) {
+void signal_unblock( int sig ) {
         sigset_t mask;
         sigemptyset( &mask );
@@ -405 +405 @@
 
 // sigprocmask wrapper : block a single signal
-static inline void signal_block( int sig ) {
+void signal_block( int sig ) {
         sigset_t mask;
         sigemptyset( &mask );