From: Eric Wong <e@80x24.org>
To: spew@80x24.org
Subject: [WIP v2 2/4] gc: rb_wait_for_single_fd performs GC if idle (Linux)
Date: Tue, 1 May 2018 08:08:42 +0000 [thread overview]
Message-ID: <20180501080844.22751-3-e@80x24.org> (raw)
In-Reply-To: <20180501080844.22751-1-e@80x24.org>
Before this patch, the entropy-dependent script below takes 95MB
consistently on my system. Now, depending on the amount of
entropy on my system, it takes anywhere from 43MB to 75MB.
I'm using /dev/urandom to simulate real-world network latency
variations. There is no improvement when using /dev/zero
because the process is never idle.
require 'net/http'
require 'digest/md5'
Thread.abort_on_exception = true
s = TCPServer.new('127.0.0.1', 0)
len = 1024 * 1024 * 1024
th = Thread.new do
c = s.accept
c.readpartial(16384)
c.write("HTTP/1.0 200 OK\r\nContent-Length: #{len}\r\n\r\n")
IO.copy_stream('/dev/urandom', c, len)
c.close
end
addr = s.addr
Net::HTTP.start(addr[3], addr[1]) do |http|
http.request_get('/') do |res|
dig = Digest::MD5.new
res.read_body { |buf|
dig.update(buf)
}
puts dig.hexdigest
end
end
The above script is also dependent on net/protocol using
read_nonblock. Ordinary IO objects will need IO#nonblock=true
to see benefits (because they never hit rb_wait_for_single_fd)
* gc.c (rb_gc_inprogress): new function
(rb_gc_step): ditto
* internal.h: declare prototypes for new gc.c functions
* thread_pthread.c (gvl_contended_p): new function
* thread_win32.c (gvl_contended_p): ditto (dummy)
* thread.c (rb_wait_for_single_fd w/ ppoll):
use new functions to perform GC while GVL is uncontended
and GC is lazy sweeping or incremental marking
[ruby-core:86265]
v2 - rb_gc_step uses *_continue functions for incremental behavior
[ruby-core:86792]
---
gc.c | 30 ++++++++++++++++++++++++++++++
internal.h | 4 ++++
thread.c | 21 +++++++++++++++------
thread_pthread.c | 6 ++++++
thread_win32.c | 6 ++++++
5 files changed, 61 insertions(+), 6 deletions(-)
diff --git a/gc.c b/gc.c
index b9c1305060..61b5e24f09 100644
--- a/gc.c
+++ b/gc.c
@@ -6518,6 +6518,36 @@ gc_rest(rb_objspace_t *objspace)
}
}
+int
+rb_gc_inprogress(const rb_execution_context_t *ec)
+{
+ rb_objspace_t *objspace = rb_ec_vm_ptr(ec)->objspace;
+
+ /* TODO: should this check is_incremental_marking() ? */
+ return is_lazy_sweeping(&objspace->eden_heap) ||
+ is_incremental_marking(objspace);
+}
+
+/* returns true if there is more work to do, false if not */
+int
+rb_gc_step(const rb_execution_context_t *ec)
+{
+ rb_objspace_t *objspace = rb_ec_vm_ptr(ec)->objspace;
+
+ if (is_lazy_sweeping(&objspace->eden_heap)) {
+#if GC_ENABLE_LAZY_SWEEP
+ gc_sweep_continue(objspace, &objspace->eden_heap);
+#endif
+ }
+ else if (is_incremental_marking(objspace)) {
+#if GC_ENABLE_INCREMENTAL_MARK
+ gc_marks_continue(objspace, &objspace->eden_heap);
+#endif
+ }
+
+ return rb_gc_inprogress(ec);
+}
+
struct objspace_and_reason {
rb_objspace_t *objspace;
int reason;
diff --git a/internal.h b/internal.h
index 85370ec0d7..43043e6601 100644
--- a/internal.h
+++ b/internal.h
@@ -1290,6 +1290,10 @@ void rb_gc_writebarrier_remember(VALUE obj);
void ruby_gc_set_params(int safe_level);
void rb_copy_wb_protected_attribute(VALUE dest, VALUE obj);
+struct rb_execution_context_struct;
+int rb_gc_inprogress(const struct rb_execution_context_struct *);
+int rb_gc_step(const struct rb_execution_context_struct *);
+
#if defined(HAVE_MALLOC_USABLE_SIZE) || defined(HAVE_MALLOC_SIZE) || defined(_WIN32)
#define ruby_sized_xrealloc(ptr, new_size, old_size) ruby_xrealloc(ptr, new_size)
#define ruby_sized_xrealloc2(ptr, new_count, element_size, old_count) ruby_xrealloc(ptr, new_count, element_size)
diff --git a/thread.c b/thread.c
index ad216f5f0c..4625d082fd 100644
--- a/thread.c
+++ b/thread.c
@@ -3962,10 +3962,12 @@ ppoll(struct pollfd *fds, nfds_t nfds,
int
rb_wait_for_single_fd(int fd, int events, struct timeval *timeout)
{
+ static const struct timespec zero;
struct pollfd fds;
int result = 0, lerrno;
struct timespec ts, end, *tsp;
rb_thread_t *th = GET_THREAD();
+ int do_gc = rb_gc_inprogress(th->ec);
timeout_prepare(&tsp, &ts, &end, timeout);
fds.fd = fd;
@@ -3974,13 +3976,20 @@ rb_wait_for_single_fd(int fd, int events, struct timeval *timeout)
do {
fds.revents = 0;
lerrno = 0;
- BLOCKING_REGION({
- result = ppoll(&fds, 1, tsp, NULL);
- if (result < 0) lerrno = errno;
- }, ubf_select, th, FALSE);
- RUBY_VM_CHECK_INTS_BLOCKING(th->ec);
- } while (result < 0 && retryable(errno = lerrno) &&
+ if (!do_gc || gvl_contended_p(th->vm)) {
+ BLOCKING_REGION({
+ result = ppoll(&fds, 1, tsp, NULL);
+ if (result < 0) lerrno = errno;
+ }, ubf_select, th, FALSE);
+ RUBY_VM_CHECK_INTS_BLOCKING(th->ec);
+ }
+ else { /* no need to release GVL if nobody is waiting for it */
+ do_gc = rb_gc_step(th->ec);
+ result = ppoll(&fds, 1, &zero, NULL);
+ if (result < 0) lerrno = errno;
+ }
+ } while ((result == 0 || (result < 0 && retryable(errno = lerrno))) &&
update_timespec(tsp, &end));
if (result < 0) return -1;
diff --git a/thread_pthread.c b/thread_pthread.c
index 6337620e8a..fccac48a44 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -156,6 +156,12 @@ gvl_yield(rb_vm_t *vm, rb_thread_t *th)
rb_native_mutex_unlock(&vm->gvl.lock);
}
+static int
+gvl_contended_p(const rb_vm_t *vm)
+{
+ return vm->gvl.waiting > 0;
+}
+
static void
gvl_init(rb_vm_t *vm)
{
diff --git a/thread_win32.c b/thread_win32.c
index ab308905cb..3e3a62dd59 100644
--- a/thread_win32.c
+++ b/thread_win32.c
@@ -113,6 +113,12 @@ gvl_yield(rb_vm_t *vm, rb_thread_t *th)
gvl_acquire(vm, th);
}
+static void
+gvl_contended_p(const rb_vm_t *vm)
+{
+ return 1; /* TODO for win32 maintainer */
+}
+
static void
gvl_init(rb_vm_t *vm)
{
--
EW
next prev parent reply other threads:[~2018-05-01 8:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-01 8:08 [WIP v2 0/4] sleepy GC Eric Wong
2018-05-01 8:08 ` [WIP v2 1/4] thread.c (timeout_prepare): common function Eric Wong
2018-05-01 8:08 ` Eric Wong [this message]
2018-05-01 8:08 ` [WIP v2 3/4] thread.c (do_select): perform GC if idle Eric Wong
2018-05-01 8:08 ` [WIP v2 4/4] thread.c: native_sleep callers may perform GC Eric Wong
2018-05-02 4:42 ` [PATCH 5/4] thread_sync.c (mutex_lock): add missing else Eric Wong
2018-05-02 4:52 ` [PATCH 6/4] gc.c: allow disabling sleepy GC Eric Wong
2018-05-02 4:57 ` [PATCH] benchmark: add benchmarks for " Eric Wong
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