This pull request converts the scheduler from a naive shared queue scheduler to a naive workstealing scheduler. The deque is still a queue inside a lock, but there is still a substantial performance gain. Fiddling with the messaging benchmark I got a ~10x speedup and observed massively reduced memory usage.
There are still *many* locations for optimization, but based on my experience so far it is a clear performance win as it is now.
This is a fairly large rollup, but I've tested everything locally, and none of
it should be platform-specific.
r=alexcrichton (bdfdbdd)
r=brson (d803c18)
r=alexcrichton (a5041d0)
r=bstrie (317412a)
r=alexcrichton (135c85e)
r=thestinger (8805baa)
r=pcwalton (0661178)
r=cmr (9397fe0)
r=cmr (caa4135)
r=cmr (6a21d93)
r=cmr (4dc3379)
r=cmr (0aa5154)
r=cmr (18be261)
r=thestinger (f10be03)
Use the definition, where R is <, <=, >=, or >
[x, ..xs] R [y, ..ys] = if x != y { x R y } else { xs R ys }
Previously, tuples would only implement < and derive the other
comparisons from it; this is incorrect. Included are several testcases
involving NaN comparisons that are now correct.
Previously, tuples would consider an element equal if both a < b and
b < a were false, this was also incorrect.
Use Eq + Ord for lexicographical ordering of sequences.
For each of <, <=, >= or > as R, use::
[x, ..xs] R [y, ..ys] = if x != y { x R y } else { xs R ys }
Previous code using `a < b` and then `!(b < a)` for short-circuiting
fails on cases such as [1.0, 2.0] < [0.0/0.0, 3.0], where the first
element was effectively considered equal.
env! aborts compilation of the specified environment variable is not
defined and takes an optional second argument containing a custom
error message. option_env! creates an Option<&'static str> containing
the value of the environment variable.
There are no run-pass tests that check the behavior when the environment
variable is defined since the test framework doesn't support setting
environment variables at compile time as opposed to runtime. However,
both env! and option_env! are used inside of rustc itself, which should
act as a sufficient test.
Close#2248
This is a reopening of #8182, although this removes any abuse of the compiler internals. Now it's just a pure syntax extension (hard coded what the attribute names are).
Write external iterators for Difference, Sym. Difference, Intersection
and Union set operations.
These iterators are generic insofar that they could work on any ordered
sequence iterators, even though they are type specialized to the
TreeSetIterator in this case.
Looking at the `check` function in the treeset tests, rustc seems
unwilling to compile a function resembling::
fn check<'a, T: Iterator<&'a int>>(... )
so the tests for these iterators are still running the legacy loop
protocol.
