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speed up IO#close with many threads

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Today, it increases IO#close performance with many threads:

  Execution time (sec)
  name            trunk   after
  vm_thread_close 4.276   3.018

  Speedup ratio: compare with the result of `trunk' (greater is better)
  name            after
  vm_thread_close 1.417

This speedup comes because rb_notify_fd_close only scans threads
inside rb_thread_io_blocking_region, not all threads in the VM.

In the future, this type data structure may allow us to notify
waiters of multiple FDs on a single thread (when using
Fibers).

* thread.c (struct waiting_fd): declare
  (rb_thread_io_blocking_region): use on-stack list waiter
  (rb_notify_fd_close): walk vm->waiting_fds instead
  (call_without_gvl): remove old field setting
  (th_init): ditto
* vm_core.h (typedef struct rb_vm_struct): add waiting_fds list
* (typedef struct rb_thread_struct): remove waiting_fd field
  (rb_vm_living_threads_init): initialize waiting_fds list

I am now kicking myself for not thinking about this 3 years ago
when I introduced ccan/list in [Feature #9632] to optimize this
same function :<

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58812 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
normal 2017-05-20 09:47:14 +00:00
parent 9cd66d7022
commit 508091d9cc
3 changed files with 19 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
thread.c
View File

@ -101,6 +101,12 @@ static int rb_threadptr_pending_interrupt_empty_p(rb_thread_t *th);
#define eTerminateSignal INT2FIX(1)
static volatile int system_working = 1;
struct waiting_fd {
struct list_node wfd_node; /* <=> vm.waiting_fds */
rb_thread_t *th;
int fd;
};
inline static void
st_delete_wrap(st_table *table, st_data_t key)
{
@ -1316,7 +1322,6 @@ call_without_gvl(void *(*func)(void *), void *data1,
rb_thread_t *th = GET_THREAD();
int saved_errno = 0;
th->waiting_fd = -1;
if (ubf == RUBY_UBF_IO || ubf == RUBY_UBF_PROCESS) {
ubf = ubf_select;
data2 = th;
@ -1439,11 +1444,15 @@ VALUE
rb_thread_io_blocking_region(rb_blocking_function_t *func, void *data1, int fd)
{
volatile VALUE val = Qundef; /* shouldn't be used */
rb_vm_t *vm = GET_VM();
rb_thread_t *th = GET_THREAD();
volatile int saved_errno = 0;
int state;
struct waiting_fd wfd;
th->waiting_fd = fd;
wfd.fd = fd;
wfd.th = th;
list_add(&vm->waiting_fds, &wfd.wfd_node);
TH_PUSH_TAG(th);
if ((state = EXEC_TAG()) == 0) {
@ -1454,8 +1463,8 @@ rb_thread_io_blocking_region(rb_blocking_function_t *func, void *data1, int fd)
}
TH_POP_TAG();
/* clear waiting_fd anytime */
th->waiting_fd = -1;
/* must be deleted before jump */
list_del(&wfd.wfd_node);
if (state) {
TH_JUMP_TAG(th, state);
@ -2196,12 +2205,13 @@ int
rb_notify_fd_close(int fd)
{
rb_vm_t *vm = GET_THREAD()->vm;
rb_thread_t *th = 0;
struct waiting_fd *wfd = 0;
int busy;
busy = 0;
list_for_each(&vm->living_threads, th, vmlt_node) {
if (th->waiting_fd == fd) {
list_for_each(&vm->waiting_fds, wfd, wfd_node) {
if (wfd->fd == fd) {
rb_thread_t *th = wfd->th;
VALUE err = th->vm->special_exceptions[ruby_error_stream_closed];
rb_threadptr_pending_interrupt_enque(th, err);
rb_threadptr_interrupt(th);

1
vm.c
View File

@ -2521,7 +2521,6 @@ th_init(rb_thread_t *th, VALUE self)
th->status = THREAD_RUNNABLE;
th->errinfo = Qnil;
th->last_status = Qnil;
th->waiting_fd = -1;
th->root_svar = Qfalse;
th->local_storage_recursive_hash = Qnil;
th->local_storage_recursive_hash_for_trace = Qnil;

4
vm_core.h
View File

@ -490,6 +490,7 @@ typedef struct rb_vm_struct {
struct rb_thread_struct *main_thread;
struct rb_thread_struct *running_thread;
struct list_head waiting_fds; /* <=> struct waiting_fd */
struct list_head living_threads;
size_t living_thread_num;
VALUE thgroup_default;
@ -716,8 +717,6 @@ typedef struct rb_thread_struct {
/* passing state */
int state;
int waiting_fd;
/* for rb_iterate */
VALUE passed_block_handler;
@ -1442,6 +1441,7 @@ void rb_thread_wakeup_timer_thread(void);
static inline void
rb_vm_living_threads_init(rb_vm_t *vm)
{
list_head_init(&vm->waiting_fds);
list_head_init(&vm->living_threads);
vm->living_thread_num = 0;
}