Reviewers: Michael Lippautz,
Description:
Allow more scavenges during idle times by pushing down the idle new space
limit.
BUG=
Please review this at https://codereview.chromium.org/1313083002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+33, -17 lines):
M src/heap/gc-idle-time-handler.cc
Index: src/heap/gc-idle-time-handler.cc
diff --git a/src/heap/gc-idle-time-handler.cc
b/src/heap/gc-idle-time-handler.cc
index
096412d578bc6b33693fb9d55aeafeb50f5d416b..b51b53b107392ee9aa2b46e399fc66da3347f1f9
100644
--- a/src/heap/gc-idle-time-handler.cc
+++ b/src/heap/gc-idle-time-handler.cc
@@ -119,13 +119,17 @@ bool GCIdleTimeHandler::ShouldDoScavenge(
// It is better to do full GC for the background tab.
return false;
}
- size_t new_space_allocation_limit =
- kMaxScheduledIdleTime * scavenge_speed_in_bytes_per_ms;
+
+ // Calculates how much memory are we able to scavenge in
+ // kMaxFrameRenderingIdleTime ms. If scavenge_speed_in_bytes_per_ms is 0
we
+ // will take care of this later.
+ size_t idle_new_space_allocation_limit =
+ kMaxFrameRenderingIdleTime * scavenge_speed_in_bytes_per_ms;
// If the limit is larger than the new space size, then scavenging used
to be
// really fast. We can take advantage of the whole new space.
- if (new_space_allocation_limit > new_space_size) {
- new_space_allocation_limit = new_space_size;
+ if (idle_new_space_allocation_limit > new_space_size) {
+ idle_new_space_allocation_limit = new_space_size;
}
// We do not know the allocation throughput before the first scavenge.
@@ -134,31 +138,43 @@ bool GCIdleTimeHandler::ShouldDoScavenge(
// We have to trigger scavenge before we reach the end of new space.
size_t adjust_limit = new_space_allocation_throughput_in_bytes_per_ms *
kTimeUntilNextIdleEvent;
- if (adjust_limit > new_space_allocation_limit) {
- new_space_allocation_limit = 0;
+ if (adjust_limit > idle_new_space_allocation_limit) {
+ idle_new_space_allocation_limit = 0;
} else {
- new_space_allocation_limit -= adjust_limit;
+ idle_new_space_allocation_limit -= adjust_limit;
}
}
- if (new_space_allocation_throughput_in_bytes_per_ms <
- kLowAllocationThroughput) {
- new_space_allocation_limit =
- Min(new_space_allocation_limit,
- static_cast<size_t>(new_space_size * kConservativeTimeRatio));
- }
-
// The allocated new space limit to trigger a scavange has to be at least
// kMinimumNewSpaceSizeToPerformScavenge.
- if (new_space_allocation_limit < kMinimumNewSpaceSizeToPerformScavenge) {
- new_space_allocation_limit = kMinimumNewSpaceSizeToPerformScavenge;
+ if (idle_new_space_allocation_limit <
kMinimumNewSpaceSizeToPerformScavenge) {
+ idle_new_space_allocation_limit =
kMinimumNewSpaceSizeToPerformScavenge;
}
+ // Set an initial scavenge speed if it is unknown.
if (scavenge_speed_in_bytes_per_ms == 0) {
scavenge_speed_in_bytes_per_ms = kInitialConservativeScavengeSpeed;
}
- if (new_space_allocation_limit <= used_new_space_size) {
+ // We apply a max factor to the new space size to make sure that a slowly
+ // allocating application still leaves enough of wiggle room to schedule
a
+ // scavenge.
+ size_t max_limit;
+ const double kMaxNewSpaceSizeFactorLongIdleTimes = 0.5;
+ const double kMaxNewSpaceSizeFactorShortIdleTimes = 0.8;
+ if (idle_time_in_ms > kMaxFrameRenderingIdleTime) {
+ max_limit = static_cast<size_t>(new_space_size *
+ kMaxNewSpaceSizeFactorLongIdleTimes);
+ } else {
+ max_limit = static_cast<size_t>(new_space_size *
+ kMaxNewSpaceSizeFactorShortIdleTimes);
+ }
+ idle_new_space_allocation_limit =
+ Min(idle_new_space_allocation_limit, max_limit);
+
+ // We perform a scavenge if we are over the idle new space limit and
+ // a scavenge fits into the given idle time bucket.
+ if (idle_new_space_allocation_limit <= used_new_space_size) {
if (used_new_space_size / scavenge_speed_in_bytes_per_ms <=
idle_time_in_ms) {
return true;
--
--
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