Changeset d3605f8

Timestamp:

Nov 29, 2021, 4:58:54 PM (18 months ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

03cdad6

Parents:

3bb4f85

Message:

Reworked io_uring idle sleep to work with either read or readv depending on what's available.

Location:

libcfa/src/concurrency

Files:

• io.cfa (modified) (3 diffs)
• io/setup.cfa (modified) (1 diff)
• kernel.cfa (modified) (8 diffs)
• kernel_private.hfa (modified) (1 diff)

libcfa/src/concurrency/io.cfa

@@ -33 +33 @@
                 #include <sys/syscall.h>
                 #include <sys/eventfd.h>
+                #include <sys/uio.h>
 
                 #include <linux/io_uring.h>
@@ -502 +503 @@
         }
 
-        #if defined(IO_URING_IDLE)
-                bool __kernel_read(processor * proc, io_future_t & future, char buf[], int fd) {
+        #if defined(CFA_WITH_IO_URING_IDLE)
+                bool __kernel_read(processor * proc, io_future_t & future, iovec & iov, int fd) {
                         $io_context * ctx = proc->io.ctx;
                         /* paranoid */ verify( ! __preemption_enabled() );
@@ -518 +519 @@
                         __fill( &sqe, 1, &idx, ctx );
 
-                        sqe->opcode = IORING_OP_READ;
                         sqe->user_data = (uintptr_t)&future;
                         sqe->flags = 0;
-                        sqe->ioprio = 0;
                         sqe->fd = fd;
                         sqe->off = 0;
+                        sqe->ioprio = 0;
                         sqe->fsync_flags = 0;
                         sqe->__pad2[0] = 0;
                         sqe->__pad2[1] = 0;
                         sqe->__pad2[2] = 0;
-                        sqe->addr = (uintptr_t)buf;
-                        sqe->len = sizeof(uint64_t);
+
+                        #if defined(CFA_HAVE_IORING_OP_READ)
+                                sqe->opcode = IORING_OP_READ;
+                                sqe->addr = (uint64_t)iov.iov_base;
+                                sqe->len = iov.iov_len;
+                        #elif defined(CFA_HAVE_READV) && defined(CFA_HAVE_IORING_OP_READV)
+                                sqe->opcode = IORING_OP_READV;
+                                sqe->addr = (uintptr_t)&iov;
+                                sqe->len = 1;
+                        #else
+                                #error CFA_WITH_IO_URING_IDLE but none of CFA_HAVE_READV, CFA_HAVE_IORING_OP_READV or CFA_HAVE_IORING_OP_READ defined
+                        #endif
 
                         asm volatile("": : :"memory");

libcfa/src/concurrency/io/setup.cfa

@@ -220 +220 @@
                 cq.cqes = (struct io_uring_cqe *)(((intptr_t)cq.ring_ptr) + params.cq_off.cqes);
 
-                #if !defined(IO_URING_IDLE)
+                #if !defined(CFA_WITH_IO_URING_IDLE)
                         // Step 4 : eventfd
                         // io_uring_register is so f*cking slow on some machine that it

libcfa/src/concurrency/kernel.cfa

@@ -27 +27 @@
 extern "C" {
         #include <sys/eventfd.h>
+        #include <sys/uio.h>
 }
 
@@ -125 +126 @@
 static void __wake_one(cluster * cltr);
 
-static void idle_sleep(processor * proc, io_future_t & future, eventfd_t & val);
+static void idle_sleep(processor * proc, io_future_t & future, iovec & iov);
 static bool mark_idle (__cluster_proc_list & idles, processor & proc);
 static void mark_awake(__cluster_proc_list & idles, processor & proc);
@@ -135 +136 @@
 static inline bool __maybe_io_drain( processor * );
 
-#if defined(IO_URING_IDLE) && defined(CFA_HAVE_LINUX_IO_URING_H)
-        extern bool __kernel_read(processor * proc, io_future_t & future, char buf[], int fd);
+#if defined(CFA_WITH_IO_URING_IDLE)
+        extern bool __kernel_read(processor * proc, io_future_t & future, iovec &, int fd);
 #endif
 
@@ -172 +173 @@
         future.self.ptr = 1p;  // mark it as already fulfilled so we know if there is a pending request or not
         eventfd_t idle_val;
+        iovec idle_iovec = { &idle_val, sizeof(idle_val) };
 
         __cfa_io_start( this );
@@ -237 +239 @@
                                 }
 
-                                idle_sleep( this, future, idle_val );
+                                idle_sleep( this, future, idle_iovec );
 
                                 // We were woken up, remove self from idle
@@ -784 +786 @@
 }
 
-static void idle_sleep(processor * this, io_future_t & future, eventfd_t & val) {
-        #if !defined(IO_URING_IDLE) || !defined(CFA_HAVE_LINUX_IO_URING_H)
+static void idle_sleep(processor * this, io_future_t & future, iovec & iov) {
+        #if !defined(CFA_WITH_IO_URING_IDLE)
                 #if !defined(__CFA_NO_STATISTICS__)
                         if(this->print_halts) {
@@ -818 +820 @@
                 #endif
         #else
-                #if !defined(CFA_HAVE_IORING_OP_READ)
-                        #error this is only implemented if the read is present
-                #endif
                 // Do we already have a pending read
                 if(available(future)) {
@@ -826 +825 @@
                         reset(future);
 
-                        __kernel_read(this, future, (char *)&val, this->idle_fd );
+                        __kernel_read(this, future, iov, this->idle_fd );
                 }
 

libcfa/src/concurrency/kernel_private.hfa

@@ -39 +39 @@
 }
 
-// #define IO_URING_IDLE
+// Defines whether or not we *want* to use io_uring_enter as the idle_sleep blocking call
+#define CFA_WANT_IO_URING_IDLE
+
+// Defines whether or not we *can* use io_uring_enter as the idle_sleep blocking call
+#if defined(CFA_WANT_IO_URING_IDLE) && defined(CFA_HAVE_LINUX_IO_URING_H)
+        #if defined(CFA_HAVE_IORING_OP_READ) || (defined(CFA_HAVE_READV) && defined(CFA_HAVE_IORING_OP_READV))
+                #define CFA_WITH_IO_URING_IDLE
+        #endif
+#endif
 
 //-----------------------------------------------------------------------------