Author: Remi Meier <[email protected]>
Branch: parallel-pulling
Changeset: r1252:a68ae11d76fa
Date: 2014-06-19 13:46 +0200
http://bitbucket.org/pypy/stmgc/changeset/a68ae11d76fa/
Log: try the most naive way to parallelize commit pushing
diff --git a/c7/stm/core.c b/c7/stm/core.c
--- a/c7/stm/core.c
+++ b/c7/stm/core.c
@@ -225,6 +225,7 @@
dprintf(("start_transaction\n"));
s_mutex_unlock();
+ pull_committed_changes();
/* Now running the SP_RUNNING start. We can set our
'transaction_read_version' after releasing the mutex,
@@ -355,7 +356,7 @@
}
}
-static void synchronize_object_now(object_t *obj)
+static void synchronize_object_now(object_t *obj, bool lazy_on_commit)
{
/* Copy around the version of 'obj' that lives in our own segment.
It is first copied into the shared pages, and then into other
@@ -381,6 +382,12 @@
uintptr_t last_page = (end - 1) / 4096UL;
long i, myself = STM_SEGMENT->segment_num;
+ bool private_in_segment[NB_SEGMENTS];
+ if (lazy_on_commit) {
+ for (i = 1; i <= NB_SEGMENTS; i++)
+ private_in_segment[i-1] = false;
+ }
+
for (; first_page <= last_page; first_page++) {
uintptr_t copy_size;
@@ -410,20 +417,25 @@
assert(memcmp(dst, src, copy_size) == 0); /* same page */
}
+ /* now copy from the shared page to all private pages */
+ src = REAL_ADDRESS(stm_object_pages, start);
for (i = 1; i <= NB_SEGMENTS; i++) {
if (i == myself)
continue;
- src = REAL_ADDRESS(stm_object_pages, start);
dst = REAL_ADDRESS(get_segment_base(i), start);
if (is_private_page(i, first_page)) {
/* The page is a private page. We need to diffuse this
fragment of object from the shared page to this private
page. */
- if (copy_size == 4096)
- pagecopy(dst, src);
- else
- memcpy(dst, src, copy_size);
+ if (!lazy_on_commit) {
+ if (copy_size == 4096)
+ pagecopy(dst, src);
+ else
+ memcpy(dst, src, copy_size);
+ }
+
+ private_in_segment[i-1] = true;
}
else {
assert(!memcmp(dst, src, copy_size)); /* same page */
@@ -432,6 +444,15 @@
start = (start + 4096) & ~4095;
}
+
+ if (lazy_on_commit) {
+ for (i = 1; i <= NB_SEGMENTS; i++) {
+ if (private_in_segment[i-1]) {
+ struct stm_priv_segment_info_s *pseg = get_priv_segment(i);
+ LIST_APPEND(pseg->outdated_objects, obj);
+ }
+ }
+ }
}
}
@@ -442,7 +463,7 @@
acquire_privatization_lock();
LIST_FOREACH_R(STM_PSEGMENT->large_overflow_objects, object_t *,
- synchronize_object_now(item));
+ synchronize_object_now(item, false));
release_privatization_lock();
}
@@ -466,7 +487,7 @@
/* copy the object to the shared page, and to the other
private pages as needed */
- synchronize_object_now(item);
+ synchronize_object_now(item, true);
}));
release_privatization_lock();
@@ -559,6 +580,7 @@
/* cannot access STM_SEGMENT or STM_PSEGMENT from here ! */
s_mutex_unlock();
+ pull_committed_changes();
}
void stm_abort_transaction(void)
@@ -567,6 +589,41 @@
abort_with_mutex();
}
+static void copy_objs_from_segment_0(int segment_num, struct list_s *lst)
+{
+ /* pull the list of objects from segment 0. This either resets
+ modifications or just updates the view of the current segment.
+ */
+ char *local_base = get_segment_base(segment_num);
+ char *zero_base = get_segment_base(0);
+
+ LIST_FOREACH_R(lst, object_t * /*item*/,
+ ({
+ /* memcpy in the opposite direction than
+ push_modified_to_other_segments() */
+ char *src = REAL_ADDRESS(zero_base, item);
+ char *dst = REAL_ADDRESS(local_base, item);
+ ssize_t size = stmcb_size_rounded_up((struct object_s *)src);
+ memcpy(dst, src, size);
+
+ /* all objs in segment 0 should have the WB flag: */
+ assert(((struct object_s *)dst)->stm_flags & GCFLAG_WRITE_BARRIER);
+ }));
+ write_fence();
+}
+
+static void pull_committed_changes()
+{
+ struct list_s *lst = STM_PSEGMENT->outdated_objects;
+
+ if (list_count(lst)) {
+ dprintf(("pulling %lu objects from shared segment\n",
list_count(lst)));
+ copy_objs_from_segment_0(STM_SEGMENT->segment_num, lst);
+ list_clear(lst);
+ }
+}
+
+
static void
reset_modified_from_other_segments(int segment_num)
{
@@ -723,6 +780,7 @@
{
s_mutex_lock();
enter_safe_point_if_requested();
+ pull_committed_changes(); /* XXX: not sure if necessary */
if (STM_PSEGMENT->transaction_state == TS_REGULAR) {
dprintf(("become_inevitable: %s\n", msg));
@@ -739,6 +797,7 @@
}
s_mutex_unlock();
+ pull_committed_changes();
}
void stm_become_globally_unique_transaction(stm_thread_local_t *tl,
@@ -749,4 +808,5 @@
s_mutex_lock();
synchronize_all_threads(STOP_OTHERS_AND_BECOME_GLOBALLY_UNIQUE);
s_mutex_unlock();
+ pull_committed_changes();
}
diff --git a/c7/stm/core.h b/c7/stm/core.h
--- a/c7/stm/core.h
+++ b/c7/stm/core.h
@@ -75,6 +75,10 @@
struct stm_priv_segment_info_s {
struct stm_segment_info_s pub;
+ /* list of objects that were committed while we waited in a
+ safe point. This means we have an outdated copy of them. */
+ struct list_s *outdated_objects;
+
/* List of old objects (older than the current transaction) that the
current transaction attempts to modify. This is used to track
the STM status: they are old objects that where written to and
@@ -257,7 +261,8 @@
}
static void copy_object_to_shared(object_t *obj, int source_segment_num);
-static void synchronize_object_now(object_t *obj);
+static void synchronize_object_now(object_t *obj, bool lazy_on_commit);
+static void pull_committed_changes();
static inline void acquire_privatization_lock(void)
{
diff --git a/c7/stm/forksupport.c b/c7/stm/forksupport.c
--- a/c7/stm/forksupport.c
+++ b/c7/stm/forksupport.c
@@ -66,6 +66,7 @@
s_mutex_lock();
synchronize_all_threads(STOP_OTHERS_UNTIL_MUTEX_UNLOCK);
+ pull_committed_changes(); /* XXX: unclear if necessary */
/* Make a new mmap at some other address, but of the same size as
the standard mmap at stm_object_pages
diff --git a/c7/stm/gcpage.c b/c7/stm/gcpage.c
--- a/c7/stm/gcpage.c
+++ b/c7/stm/gcpage.c
@@ -153,6 +153,7 @@
}
s_mutex_unlock();
+ pull_committed_changes();
}
diff --git a/c7/stm/nursery.c b/c7/stm/nursery.c
--- a/c7/stm/nursery.c
+++ b/c7/stm/nursery.c
@@ -216,7 +216,7 @@
*/
if (STM_PSEGMENT->minor_collect_will_commit_now) {
acquire_privatization_lock();
- synchronize_object_now(obj);
+ synchronize_object_now(obj, false);
release_privatization_lock();
} else {
LIST_APPEND(STM_PSEGMENT->large_overflow_objects, obj);
diff --git a/c7/stm/setup.c b/c7/stm/setup.c
--- a/c7/stm/setup.c
+++ b/c7/stm/setup.c
@@ -118,6 +118,7 @@
pr->pub.segment_base = segment_base;
pr->objects_pointing_to_nursery = NULL;
pr->large_overflow_objects = NULL;
+ pr->outdated_objects = list_create();
pr->modified_old_objects = list_create();
pr->modified_old_objects_markers = list_create();
pr->young_weakrefs = list_create();
@@ -157,6 +158,7 @@
struct stm_priv_segment_info_s *pr = get_priv_segment(i);
assert(pr->objects_pointing_to_nursery == NULL);
assert(pr->large_overflow_objects == NULL);
+ list_free(pr->outdated_objects);
list_free(pr->modified_old_objects);
list_free(pr->modified_old_objects_markers);
list_free(pr->young_weakrefs);
diff --git a/c7/stm/sync.c b/c7/stm/sync.c
--- a/c7/stm/sync.c
+++ b/c7/stm/sync.c
@@ -255,6 +255,7 @@
STM_PSEGMENT->safe_point = SP_RUNNING;
stm_safe_point();
+ pull_committed_changes();
}
#endif
@@ -439,4 +440,5 @@
s_mutex_lock();
enter_safe_point_if_requested();
s_mutex_unlock();
+ pull_committed_changes();
}
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