Use a lookup table, SHIFT_MASK_TABLE, that for every possible four
bit prefix holds the number of times the value should be right shifted and what
the right shifted value should be masked with. This way we can get rid of the
branches which in my testing gives approximately a 2x speedup.
Since reader::vuint_at() returns a result of type reader::Res it makes sense
to make it public.
Due to rust's current behavior of externally referenced private structures,
https://github.com/mozilla/rust/issues/10573, you could still use the result and
assign it to a variable if you let the compiler do the type assignment,
but you could not explicitly annotate a variable to hold a reader::Res.
The `print!` and `println!` macros are now the preferred method of printing, and so there is no reason to export the `stdio` functions in the prelude. The functions have also been replaced by their macro counterparts in the tutorial and other documentation so that newcomers don't get confused about what they should be using.
The methods contained in `std::num::{Algebraic, Trigonometric, Exponential, Hyperbolic}` have now been moved into `std::num::Real`. This is part of an ongoing effort to simplify `std::num` (see issue #10387).
`std::num::RealExt` has also been removed from the prelude because it is not a commonly used trait.
r? @alexcrichton
This trait seems to stray too far from the mandate of a standard library as implementations may vary between use cases. Third party libraries should implement their own if they need something like it.
This closes#5316.
r? @alexcrichton, @pcwalton
This is just an unnecessary trait that no one's ever going to parameterize over
and it's more useful to just define the methods directly on the types
themselves. The implementors of this type almost always don't want
inner_mut_ref() but they're forced to define it as well.
The methods contained in `std::num::{Algebraic, Trigonometric, Exponential, Hyperbolic}` have now been moved into `std::num::Real`. This is part of an ongoing effort to simplify `std::num` (see issue #10387).
`std::num::RealExt` has also been removed from the prelude because it is not a commonly used trait.
A typed arena is a type of arena that can only allocate objects of one
type. It is 3x faster than the existing arena and 13x faster than malloc
on Mac.
r? @brson
A typed arena is a type of arena that can only allocate objects of one
type. It is 3x faster than the existing arena and 13x faster than malloc
on Mac.
Apologies for junking up the feed with all of these separate pull requests. I'm still getting the hang of git and will hopefully be doing less of this nonsense soon. I opened up another PR and closed the one from earlier today because the first PR was coming from the wrong branch of my repo.
Anyway, this contains a fleshed-out implementation of TotalEq/TotalOrd/Clone/ToStr for the whole B-tree structure and relevant tests, integrating suggestions and comments from several community members.
r? @catamorphism
- Add `mut_iter`, `mut_lower_bound`, `mut_upper_bound`
- Remove some internal iterators
- Add benchmarks
- Improve performance of `{mut_,}{lower,upper}_bound`
- Minor clean-up of `extra::treemap` after I realised I wasn't exploiting macros to their full DRY potential.
After writing some benchmarks for ebml::reader::vuint_at() I noticed that LLVM doesn't seem to inline the from_be32 function even though it only does a call to the bswap32 intrinsic in the x86_64 case. Marking the functions with #[inline(always)] fixes that and seems to me a reasonable thing to do. I got the following measurements in my vuint_at() benchmarks:
- Before
test ebml::bench::vuint_at_A_aligned ... bench: 1075 ns/iter (+/- 58)
test ebml::bench::vuint_at_A_unaligned ... bench: 1073 ns/iter (+/- 5)
test ebml::bench::vuint_at_D_aligned ... bench: 1150 ns/iter (+/- 5)
test ebml::bench::vuint_at_D_unaligned ... bench: 1151 ns/iter (+/- 6)
- Inline from_be32
test ebml::bench::vuint_at_A_aligned ... bench: 769 ns/iter (+/- 9)
test ebml::bench::vuint_at_A_unaligned ... bench: 795 ns/iter (+/- 6)
test ebml::bench::vuint_at_D_aligned ... bench: 758 ns/iter (+/- 8)
test ebml::bench::vuint_at_D_unaligned ... bench: 759 ns/iter (+/- 8)
- Using vuint_at_slow()
test ebml::bench::vuint_at_A_aligned ... bench: 646 ns/iter (+/- 7)
test ebml::bench::vuint_at_A_unaligned ... bench: 645 ns/iter (+/- 3)
test ebml::bench::vuint_at_D_aligned ... bench: 907 ns/iter (+/- 4)
test ebml::bench::vuint_at_D_unaligned ... bench: 1085 ns/iter (+/- 16)
As expected inlining from_be32() gave a considerable speedup.
I also tried how the "slow" version fared against the optimized version and noticed that it's
actually a bit faster for small A class integers (using only two bytes) but slower for big D class integers (using four bytes)
