1370181 - Don't start possibly-long-running GC work when there's not much time left in the budget

Status: NEW

(Core :: JavaScript: GC, enhancement, P3)

Description

[Jon Coppeard (:jonco)]

We have a couple of places in the GC where we defer work that must be performed atomically w.r.t. the mutator and may overrun the slice budget to a new slice.  

When we start to have slices triggered from idle timers we may get very short slice budgets (e.g. 2ms) so rather than waiting for the next slice (which may be very short) we should check the remaining budget against some minimum before starting work that we think may may overrun.  This would mean we may do nothing for a few slices until we get one that is large enough so we may want to cap the number of skipped slices too.

Comment 1

[Jon Coppeard (:jonco)]

I'm moving this to P3 since I don't think that this change would have much effect.  We already yield at start of sweeping for this reason.  Other changes that are in progress (incrementalising gray and weak marking) would have a greater impact here.