It isn't specific to maps, so put it in a more general location.
For #54766.
Change-Id: Ia3f3ebe8c347cfa5a8582082a306f4df4e05818d
Reviewed-on: https://go-review.googlesource.com/c/go/+/580777
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Make sure to alloc+copy large keys and values instead of aliasing them,
when they might be updated by a future assignment.
Fixes#64474
Change-Id: Ie2226a81cf3897e4e2ee24472f2966d397ace53f
Reviewed-on: https://go-review.googlesource.com/c/go/+/546515
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
This change replaces the 1-bit-per-word heap bitmap for most size
classes with allocation headers for objects that contain pointers. The
header consists of a single pointer to a type. All allocations with
headers are treated as implicitly containing one or more instances of
the type in the header.
As the name implies, headers are usually stored as the first word of an
object. There are two additional exceptions to where headers are stored
and how they're used.
Objects smaller than 512 bytes do not have headers. Instead, a heap
bitmap is reserved at the end of spans for objects of this size. A full
word of overhead is too much for these small objects. The bitmap is of
the same format of the old bitmap, minus the noMorePtrs bits which are
unnecessary. All the objects <512 bytes have a bitmap less than a
pointer-word in size, and that was the granularity at which noMorePtrs
could stop scanning early anyway.
Objects that are larger than 32 KiB (which have their own span) have
their headers stored directly in the span, to allow power-of-two-sized
allocations to not spill over into an extra page.
The full implementation is behind GOEXPERIMENT=allocheaders.
The purpose of this change is performance. First and foremost, with
headers we no longer have to unroll pointer/scalar data at allocation
time for most size classes. Small size classes still need some
unrolling, but their bitmaps are small so we can optimize that case
fairly well. Larger objects effectively have their pointer/scalar data
unrolled on-demand from type data, which is much more compactly
represented and results in less TLB pressure. Furthermore, since the
headers are usually right next to the object and where we're about to
start scanning, we get an additional temporal locality benefit in the
data cache when looking up type metadata. The pointer/scalar data is
now effectively unrolled on-demand, but it's also simpler to unroll than
before; that unrolled data is never written anywhere, and for arrays we
get the benefit of retreading the same data per element, as opposed to
looking it up from scratch for each pointer-word of bitmap. Lastly,
because we no longer have a heap bitmap that spans the entire heap,
there's a flat 1.5% memory use reduction. This is balanced slightly by
some objects possibly being bumped up a size class, but most objects are
not tightly optimized to size class sizes so there's some memory to
spare, making the header basically free in those cases.
See the follow-up CL which turns on this experiment by default for
benchmark results. (CL 538217.)
Change-Id: I4c9034ee200650d06d8bdecd579d5f7c1bbf1fc5
Reviewed-on: https://go-review.googlesource.com/c/go/+/437955
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
We were using the size stored in the map, which is the smaller
of the real type size and 128.
As of CL 61538 we don't use these functions, but we expect to
use them again in the future after #61626 is resolved.
Change-Id: I7bfb4af5f0e3a56361d4019a8ed7c1ec59ff31fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/535215
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Keith Randall <khr@google.com>
The correct load factor is 6.5, not 6.
This got broken by accident in CL 462115.
Fixes#63438
Change-Id: Ib07bb6ab6103aec87cb775bc06bd04362a64e489
Reviewed-on: https://go-review.googlesource.com/c/go/+/533279
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
name old time/op new time/op delta
Values-10 8.67ms ± 0% 7.19ms ± 2% -17.05% (p=0.000 n=9+10)
name old alloc/op new alloc/op delta
Values-10 58.2kB ± 2% 48.3kB ± 2% -17.14% (p=0.000 n=9+10)
name old allocs/op new allocs/op delta
Values-10 0.00 0.00 ~ (all equal)
Change-Id: Idd35ea37514a21d97bdd6191c8fb8a478c00e414
Reviewed-on: https://go-review.googlesource.com/c/go/+/481436
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: xie cui <523516579@qq.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Currently, reflect.ValueOf forces the referenced object to be heap
allocated. This CL makes it possible to be stack allocated. We
need to be careful to make sure the compiler's escape analysis can
do the right thing, e.g. channel send, map assignment, unsafe
pointer conversions.
Tests will be added in a later CL.
CL 408827 might help ensure the correctness.
Change-Id: I8663651370c7c8108584902235062dd2b3f65954
Reviewed-on: https://go-review.googlesource.com/c/go/+/408826
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This touches a lot of files, which is bad, but it is also good,
since there's N copies of this information commoned into 1.
The new files in internal/abi are copied from the end of the stack;
ultimately this will all end up being used.
Change-Id: Ia252c0055aaa72ca569411ef9f9e96e3d610889e
Reviewed-on: https://go-review.googlesource.com/c/go/+/462995
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
So iterators that are in progress can know entries have been deleted and
terminate the iterator properly.
Update #55002
Update #56351Fixes#59411
Change-Id: I924f16a00fe4ed6564f730a677348a6011d3fb67
Reviewed-on: https://go-review.googlesource.com/c/go/+/481935
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Previously TryBot-tested with bucket bits = 4.
Also tested locally with bucket bits = 5.
This makes it much easier to change the size of map
buckets, and hopefully provides pointers to all the
code that in some way depends on details of map layout.
Change-Id: I9f6669d1eadd02f182d0bc3f959dc5f385fa1683
Reviewed-on: https://go-review.googlesource.com/c/go/+/462115
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Change-Id: I69065f8adf101fdb28682c55997f503013a50e29
Reviewed-on: https://go-review.googlesource.com/c/go/+/449757
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Joedian Reid <joedian@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Joedian Reid <joedian@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
"User" throws are throws due to some invariant broken by the application.
"System" throws are due to some invariant broken by the runtime,
environment, etc (i.e., not the fault of the application).
This CL sends "user" throws through the new fatal. Currently this
function is identical to throw, but with a different name to clearly
differentiate the throw type in the stack trace, and hopefully be a bit
more clear to users what it means.
This CL changes a few categories of throw to fatal:
1. Concurrent map read/write.
2. Deadlock detection.
3. Unlock of unlocked sync.Mutex.
4. Inconsistent results from syscall.AllThreadsSyscall.
"Thread exhaustion" and "out of memory" (usually address space full)
throws are additional throws that are arguably the fault of user code,
but I've left off for now because there is no specific invariant that
they have broken to get into these states.
For #51485
Change-Id: I713276a6c290fd34a6563e6e9ef378669d74ae32
Reviewed-on: https://go-review.googlesource.com/c/go/+/390420
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Change-Id: I5698c7576a0f39ae62de7bea64286ac8e578d421
Reviewed-on: https://go-review.googlesource.com/c/go/+/400916
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Add explicit address sanitizer instrumentation to the runtime and
syscall packages. The compiler does not instrument the runtime
package. It does instrument the syscall package, but we need to add
a couple of cases that it can't see.
Refer to the implementation of the asan malloc runtime library,
this patch also allocates extra memory as the redzone, around the
returned memory region, and marks the redzone as unaddressable to
detect the overflows or underflows.
Updates #44853.
Change-Id: I2753d1cc1296935a66bf521e31ce91e35fcdf798
Reviewed-on: https://go-review.googlesource.com/c/go/+/298614
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: fannie zhang <Fannie.Zhang@arm.com>
Over 80% of all Go map types use a string as the key.
The Go runtime already has a specialized implementation for such maps
in runtime/map_faststr.go. However, the Go reflection implementation
has not historically made use of that implementation.
This CL plumbs the appropriate logic to be accessible from Go reflection
so that it can benefit as well.
name old time/op new time/op delta
Map/StringKeys/MapIndex-4 4.65us ± 5% 2.95us ± 3% -36.50% (p=0.016 n=4+5)
Map/StringKeys/SetMapIndex-4 7.47us ± 5% 5.27us ± 2% -29.40% (p=0.008 n=5+5)
Map/Uint64Keys/MapIndex-4 3.79us ± 3% 3.75us ± 2% ~ (p=0.548 n=5+5)
Map/Uint64Keys/SetMapIndex-4 6.13us ± 3% 6.09us ± 1% ~ (p=0.746 n=5+5)
Change-Id: I5495d48948d8caf2d004a03ae1820ab5f8729670
Reviewed-on: https://go-review.googlesource.com/c/go/+/345486
Trust: Joe Tsai <joetsai@digital-static.net>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This reduces the number of allocations per
reflect map iteration from two to one.
For #46293
Change-Id: Ibcff5f42fc512e637b6e460bad4518e7ac83d4c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/321889
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
At this point all funcPC references are ABIInternal functions.
Replace with the intrinsics.
Change-Id: I3ba7e485c83017408749b53f92877d3727a75e27
Reviewed-on: https://go-review.googlesource.com/c/go/+/321954
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This harmonizes the syntax between mapaccess1 and mapaccess2, and
simplifies the code.
Change-Id: I6db25ffdc871018d399f9030259894b3994c5793
Reviewed-on: https://go-review.googlesource.com/c/go/+/308951
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
update comment cause gc/reflect.go has been moved to reflectdata/reflect.go
In the commit (attach below), gc/reflect.go is moved to reflectdata/reflect.go
So the comment referring gc/reflect.go should be updated to reflectdata/reflect.go
There maybe other places that refers gc/reflect.go that should be updated.
I would work around it soon.
commit:
de65151e50e4895ab4c0
Change-Id: Ieed5c48049ffe6889c08e164972fc7825653ac05
GitHub-Last-Rev: eec9c2328d
GitHub-Pull-Request: golang/go#45421
Reviewed-on: https://go-review.googlesource.com/c/go/+/307930
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
The file "cmd/internal/gc/range.go" does not exist, but should be
"cmd/compile/internal/gc/range.go".
Change-Id: I26e5560b9d0b7eea8502c6b375e45fc87aed1276
GitHub-Last-Rev: 5f19dca7e9
GitHub-Pull-Request: golang/go#42391
Reviewed-on: https://go-review.googlesource.com/c/go/+/267837
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
1.Revise ambiguous comments: "all current buckets" means buckets in hmap.buckets, actually current bucket and all the overflow buckets connected to it are full
2.All the pointer address add use src/runtime/stubs.go:add, keep the code style uniform
Change-Id: Idc7224dbe6c391e1b03bf5d009c3734bc75187ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/257979
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
In the common case (<1KB types), no allocation is required
by reflect.Zero.
Also use memclr instead of memmove in Set when the source
is known to be zero.
Fixes#33136
Change-Id: Ic66871930fbb53328032e587153ebd12995ccf55
Reviewed-on: https://go-review.googlesource.com/c/go/+/192331
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Right now we generate hash functions for all types, just in case they
are used as map keys. That's a lot of wasted effort and binary size
for types which will never be used as a map key. Instead, generate
hash functions only for types that we know are map keys.
Just doing that is a bit too simple, since maps with an interface type
as a key might have to hash any concrete key type that implements that
interface. So for that case, implement hashing of such types at
runtime (instead of with generated code). It will be slower, but only
for maps with interface types as keys, and maybe only a bit slower as
the aeshash time probably dominates the dispatch time.
Reorg where we keep the equals and hash functions. Move the hash function
from the key type to the map type, saving a field in every non-map type.
That leaves only one function in the alg structure, so get rid of that and
just keep the equal function in the type descriptor itself.
cmd/go now has 10 generated hash functions, instead of 504. Makes
cmd/go 1.0% smaller. Update #6853.
Speed on non-interface keys is unchanged. Speed on interface keys
is ~20% slower:
name old time/op new time/op delta
MapInterfaceString-8 23.0ns ±21% 27.6ns ±14% +20.01% (p=0.002 n=10+10)
MapInterfacePtr-8 19.4ns ±16% 23.7ns ± 7% +22.48% (p=0.000 n=10+8)
Change-Id: I7c2e42292a46b5d4e288aaec4029bdbb01089263
Reviewed-on: https://go-review.googlesource.com/c/go/+/191198
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
The spec carefully and consistently uses "key" and "element"
as map terminology. The implementation, not so much.
This change attempts to make the implementation consistently
hew to the spec's terminology. Beyond consistency, this has
the advantage of avoid some confusion and naming collisions,
since v and value are very generic and commonly used terms.
I believe that I found all everything, but there are a lot of
non-obvious places for these to hide, and grepping for them is hard.
Hopefully this change changes enough of them that we will start using
elem going forward. Any remaining hidden cases can be removed ad hoc
as they are discovered.
The only externally-facing part of this change is in package reflect,
where there is a minor doc change and a function parameter name change.
Updates #27167
Change-Id: I2f2d78f16c360dc39007b9966d5c2046a29d3701
Reviewed-on: https://go-review.googlesource.com/c/go/+/174523
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently the shift amount is only masked on x86. Change it so it
is masked on all architectures. In the worst case we generate a
couple of extra instructions to perform the masking and in the best
case we can elide overflow checks.
This particular shift could also be replaced with a rotate
instruction during optimization which would remove both the masking
instructions and overflow checks on all architectures.
Fixes#31165.
Change-Id: I16b7a8800b4ba8813dc83735dfc59564e661d3b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/170122
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Now the net package is back to no longer depending on unicode. And lock that in
with a test.
Fixes#30440
Change-Id: I18b89b02f7d96488783adc07308da990f505affd
Reviewed-on: https://go-review.googlesource.com/c/go/+/169137
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
We already have the ptrdata field in a type, which encodes exactly
the same information that kindNoPointers does.
My problem with kindNoPointers is that it often leads to
double-negative code like:
t.kind & kindNoPointers != 0
Much clearer is:
t.ptrdata == 0
Update #27167
Change-Id: I92307d7f018a6bbe3daca4a4abb4225e359349b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/169157
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reorg map flags a bit so we don't need any extra space for the extra flag.
Fixes#23734
Change-Id: I436812156240ae90de53d0943fe1aabf3ea37417
Reviewed-on: https://go-review.googlesource.com/c/155918
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When we delete an element, and it was the last element in the bucket,
update the slots between the new last element and the old last element
with the marker that says "no more elements beyond here".
Change-Id: I8efeeddf4c9b9fc491c678f84220a5a5094c9c76
Reviewed-on: https://go-review.googlesource.com/c/142438
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
