Allocate a C enum object, and test if it can be assigned a value
successfully.
For #39537
Change-Id: I7b5482112486440b9d99f2ee4051328d87f45dca
GitHub-Last-Rev: 81890f40ac
GitHub-Pull-Request: golang/go#39977
Reviewed-on: https://go-review.googlesource.com/c/go/+/240697
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Change the scheduler to treat expired timers with the same approach it
uses to steal runnable G's.
Previously the scheduler ignored timers on P's not marked for
preemption. That had the downside that any G's waiting on those expired
timers starved until the G running on their P completed or was
preempted. That could take as long as 20ms if sysmon was in a 10ms
wake up cycle.
In addition, a spinning P that ignored an expired timer and found no
other work would stop despite there being available work, missing the
opportunity for greater parallelism.
With this change the scheduler no longer ignores timers on
non-preemptable P's or relies on sysmon as a backstop to start threads
when timers expire. Instead it wakes an idle P, if needed, when
creating a new timer because it cannot predict if the current P will
have a scheduling opportunity before the new timer expires. The P it
wakes will determine how long to sleep and block on the netpoller for
the required time, potentially stealing the new timer when it wakes.
This change also eliminates a race between a spinning P transitioning
to idle concurrently with timer creation using the same pattern used
for submission of new goroutines in the same window.
Benchmark analysis:
CL 232199, which was included in Go 1.15 improved timer latency over Go
1.14 by allowing P's to steal timers from P's not marked for preemption.
The benchmarks added in this CL measure that improvement in the
ParallelTimerLatency benchmark seen below. However, Go 1.15 still relies
on sysmon to notice expired timers in some situations and sysmon can
sleep for up to 10ms before waking to check timers. This CL fixes that
shortcoming with modest regression on other benchmarks.
name \ avg-late-ns go14.time.bench go15.time.bench fix.time.bench
ParallelTimerLatency-8 17.3M ± 3% 7.9M ± 0% 0.2M ± 3%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=1-8 53.4k ±23% 50.7k ±31% 252.4k ± 9%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=2-8 204k ±14% 90k ±58% 188k ±12%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=3-8 1.17M ± 0% 0.11M ± 5% 0.11M ± 2%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=4-8 1.81M ±44% 0.10M ± 4% 0.10M ± 2%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=5-8 2.28M ±66% 0.09M ±13% 0.08M ±21%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=6-8 2.84M ±85% 0.07M ±15% 0.07M ±18%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=7-8 2.13M ±27% 0.06M ± 4% 0.06M ± 9%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=8-8 2.63M ± 6% 0.06M ±11% 0.06M ± 9%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=9-8 3.32M ±17% 0.06M ±16% 0.07M ±14%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=10-8 8.46M ±20% 4.37M ±21% 5.03M ±23%
StaggeredTickerLatency/work-dur=2ms/tickers-per-P=1-8 1.02M ± 1% 0.20M ± 2% 0.20M ± 2%
name \ max-late-ns go14.time.bench go15.time.bench fix.time.bench
ParallelTimerLatency-8 18.3M ± 1% 8.2M ± 0% 0.5M ±12%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=1-8 141k ±19% 127k ±19% 1129k ± 3%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=2-8 2.78M ± 4% 1.23M ±15% 1.26M ± 5%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=3-8 6.05M ± 5% 0.67M ±56% 0.81M ±33%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=4-8 7.93M ±20% 0.71M ±46% 0.76M ±41%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=5-8 9.41M ±30% 0.92M ±23% 0.81M ±44%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=6-8 10.8M ±42% 0.8M ±41% 0.8M ±30%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=7-8 9.62M ±24% 0.77M ±38% 0.88M ±27%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=8-8 10.6M ±10% 0.8M ±32% 0.7M ±27%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=9-8 11.9M ±36% 0.6M ±46% 0.8M ±38%
StaggeredTickerLatency/work-dur=300µs/tickers-per-P=10-8 36.8M ±21% 24.7M ±21% 27.5M ±16%
StaggeredTickerLatency/work-dur=2ms/tickers-per-P=1-8 2.12M ± 2% 1.02M ±11% 1.03M ± 7%
Other time benchmarks:
name \ time/op go14.time.bench go15.time.bench fix.time.bench
AfterFunc-8 137µs ± 4% 123µs ± 4% 131µs ± 2%
After-8 212µs ± 3% 195µs ± 4% 204µs ± 7%
Stop-8 165µs ± 6% 156µs ± 2% 151µs ±12%
SimultaneousAfterFunc-8 260µs ± 3% 248µs ± 3% 284µs ± 2%
StartStop-8 65.8µs ± 9% 64.4µs ± 7% 67.3µs ±15%
Reset-8 13.6µs ± 2% 9.6µs ± 2% 9.1µs ± 4%
Sleep-8 307µs ± 4% 306µs ± 3% 320µs ± 2%
Ticker-8 53.0µs ± 5% 54.5µs ± 5% 57.0µs ±11%
TickerReset-8 9.24µs ± 2% 9.51µs ± 3%
TickerResetNaive-8 149µs ± 5% 145µs ± 5%
Fixes#38860
Updates #25471
Updates #27707
Change-Id: If52680509b0f3b66dbd1d0c13fa574bd2d0bbd57
Reviewed-on: https://go-review.googlesource.com/c/go/+/232298
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Trust: Ian Lance Taylor <iant@golang.org>
misc/cgo/test fails in 'dist test' on arm64 if the C compiler is of GCC-9.4 or
above and its 'outline atomics' feature is enabled, since the internal linking
hasn't yet supported "__attribute__((constructor))" and also mis-handles hidden
visibility.
This change addresses the problem by skipping the internal linking cases of
misc/cgo/test on linux/arm64. It fixes 'dist test' failure only, user is expected to
pass a GCC option '-mno-outline-atomics' via CGO_CFLAGS if running into the same
problem when building cgo programs using internal linking.
Updates #39466
Change-Id: I57f9e85fca881e5fd2dae6c1b4446bce9e0c1975
Reviewed-on: https://go-review.googlesource.com/c/go/+/262357
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Glob is needed for //go:embed processing.
Also change TestReadDir to be deterministic
and print more output about failures.
Change-Id: Ie22a9c5b32bda753579ff98cec1d28e3244c4e06
Reviewed-on: https://go-review.googlesource.com/c/go/+/264538
Trust: Russ Cox <rsc@golang.org>
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Previously, 2 goroutines were created in OpenDB and a comment in the DB.close() field indicated that they were canceled. Later, session Resetter () was removed, but the comment remained the same. This commit just fixes this message
Change-Id: Ie81026f51d7770e9cf8004818154021f626fb2e8
GitHub-Last-Rev: 38b338a0d1
GitHub-Pull-Request: golang/go#42191
Reviewed-on: https://go-review.googlesource.com/c/go/+/264838
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Trust: Brad Fitzpatrick <bradfitz@golang.org>
Add additional rules to eliminate unnecessary sign/zero extension for riscv64.
Also where possible, replace an extension following a load with a different typed
load. This removes almost another 8,000 instructions from the go binary.
Of particular note, change Eq16/Eq8/Neq16/Neq8 to zero extend each value before
subtraction, rather than zero extending after subtraction. While this appears to
double the number of zero extensions, it often lets us completely eliminate them
as the load can already be performed in a properly typed manner.
As an example, prior to this change runtime.memequal16 was:
0000000000013028 <runtime.memequal16>:
13028: 00813183 ld gp,8(sp)
1302c: 00019183 lh gp,0(gp)
13030: 01013283 ld t0,16(sp)
13034: 00029283 lh t0,0(t0)
13038: 405181b3 sub gp,gp,t0
1303c: 03019193 slli gp,gp,0x30
13040: 0301d193 srli gp,gp,0x30
13044: 0011b193 seqz gp,gp
13048: 00310c23 sb gp,24(sp)
1304c: 00008067 ret
Whereas it now becomes:
0000000000012fa8 <runtime.memequal16>:
12fa8: 00813183 ld gp,8(sp)
12fac: 0001d183 lhu gp,0(gp)
12fb0: 01013283 ld t0,16(sp)
12fb4: 0002d283 lhu t0,0(t0)
12fb8: 405181b3 sub gp,gp,t0
12fbc: 0011b193 seqz gp,gp
12fc0: 00310c23 sb gp,24(sp)
12fc4: 00008067 ret
Change-Id: I16321feb18381241cab121c0097a126104c56c2c
Reviewed-on: https://go-review.googlesource.com/c/go/+/264659
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
CryptGenRandom appears to be unfavorable these days, whereas the classic
RtlGenRandom is still going strong.
This commit also moves the warnBlocked function into rand_unix, rather
than rand, because it's now only used on unix.
Fixes#33542
Change-Id: I5c02a5917572f54079d627972401efb6e1ce4057
Reviewed-on: https://go-review.googlesource.com/c/go/+/210057
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than handling sign and zero extension via rules, defer to the assembler
and use MOV pseudo-instructions. The instruction can also be omitted where the
type and size is already correct. This change results in more than 6,000
instructions being removed from the go binary (in part due to omitted
instructions, in part due to MOVBU having a more efficient implementation in
the assembler than what is used in the current ZeroExt8to{16,32,64} rules).
This will also allow for further rewriting to remove redundant sign/zero
extension.
Change-Id: I05e42fd9f09f40a69948be7de772cce8946c8744
Reviewed-on: https://go-review.googlesource.com/c/go/+/264658
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Instead of duplicating PackageOpts fields in the loaderParams struct,
embed the PackageOpts directly. Many of the fields are duplicated, and
further fields that would also be duplicated will be added in
subsequent changes.
For #36460
Change-Id: I3b0770d162e901d23ec1643183eb07c413d51e0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/263138
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
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Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
This reverts CL 252478.
Reason for revert: debug/Elfhdr has no Flags fields, some other CLs has removed it.
Change-Id: Ie199ac29f382c56aaf37a2e8338f2dafe6e79297
Reviewed-on: https://go-review.googlesource.com/c/go/+/265317
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Meng Zhuo <mzh@golangcn.org>
Add support for Thread Local Storage (TLS) for linux/riscv64 with external
linking, using the initial-exec model.
Update #36641
Change-Id: I3106ef9a29cde73215830b00deff43dbec1c76e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/263478
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
Enable c-archive, c-shared, shared and pie build modes for linux/riscv64.
Change-Id: I15a8a51b84dbbb82a5b6592aec84a7f09f0cc37f
Reviewed-on: https://go-review.googlesource.com/c/go/+/263457
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Currently, "x &^ y" gets rewriten into "x & ^y" during walk. It adds
unnecessary complexity to other parts, which must aware about this.
Instead, we can just implement "&^" in the conversion to SSA, so "&^"
can be handled like other binary operators.
However, this CL does not pass toolstash-check. It seems that implements
"&^" in the conversion to SSA causes registers allocation change.
With the parent:
obj: 00212 (.../src/runtime/complex.go:47) MOVQ X0, AX
obj: 00213 (.../src/runtime/complex.go:47) BTRQ $63, AX
obj: 00214 (.../src/runtime/complex.go:47) MOVQ "".n(SP), CX
obj: 00215 (.../src/runtime/complex.go:47) MOVQ $-9223372036854775808, DX
obj: 00216 (.../src/runtime/complex.go:47) ANDQ DX, CX
obj: 00217 (.../src/runtime/complex.go:47) ORQ AX, CX
With this CL:
obj: 00212 (.../src/runtime/complex.go:47) MOVQ X0, AX
obj: 00213 (.../src/runtime/complex.go:47) BTRQ $63, AX
obj: 00214 (.../src/runtime/complex.go:47) MOVQ $-9223372036854775808, CX
obj: 00215 (.../src/runtime/complex.go:47) MOVQ "".n(SP), DX
obj: 00216 (.../src/runtime/complex.go:47) ANDQ CX, DX
obj: 00217 (.../src/runtime/complex.go:47) ORQ AX, DX
Change-Id: I80acf8496a91be4804fb7ef3df04c19baae2754c
Reviewed-on: https://go-review.googlesource.com/c/go/+/264660
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
For follow up CL, which will defer lowering OANDNOT until SSA.
Change-Id: I5a988d0b8f0ae664580f08b123811b2a31ef55c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/265040
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This change modifies addrRanges.findSucc to more efficiently find the
successor range in an addrRanges by using a binary search to narrow down
large addrRanges and iterate over no more than 8 addrRanges.
This change makes the runtime more robust against systems that may
aggressively randomize the address space mappings it gives the runtime
(e.g. Fuchsia).
For #40191.
Change-Id: If529df2abd2edb1b1496d8690ddd284ecd7138c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/242679
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Since MemStats is now populated directly and some values are derived,
avoid duplicating the logic by instead populating the heap dump directly
from MemStats (external version) instead of memstats (runtime internal
version).
Change-Id: I0bec96bfa02d2ffd1b56475779c124a760e64238
Reviewed-on: https://go-review.googlesource.com/c/go/+/255817
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
For #37112.
Change-Id: I994dfe848605b95ef6aec24f53869e929247e987
Reviewed-on: https://go-review.googlesource.com/c/go/+/247049
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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For #37112.
Change-Id: Ibb0425c9c582ae3da3b2662d5bbe830d7df9079c
Reviewed-on: https://go-review.googlesource.com/c/go/+/247047
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This change adds a concurrent HDR time histogram to the runtime with
tests. It also adds a function to generate boundaries for use by the
metrics package.
For #37112.
Change-Id: Ifbef8ddce8e3a965a0dcd58ccd4915c282ae2098
Reviewed-on: https://go-review.googlesource.com/c/go/+/247046
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Michael Pratt <mpratt@google.com>
This change adds metrics for the distribution of objects allocated and
freed by size, mirroring MemStats' BySize field.
For #37112.
Change-Id: Ibaf1812da93598b37265ec97abc6669c1a5efcbf
Reviewed-on: https://go-review.googlesource.com/c/go/+/247045
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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CL 253748 introduced a special case in cmd/go to allow sync to import
runtime/internal/atomic. Besides introducing unnecessary complexity
into cmd/go, this breaks other packages (like gopls) that understand
how imports work, but don't understand this special case.
Fix this by using the more standard linkname-based approach to pull
the necessary functions from runtime/internal/atomic into sync. Since
these are compiler intrinsics, we also have to tell the compiler that
the linknamed symbols are intrinsics to get this optimization in sync.
Fixes#42196.
Change-Id: I1f91498c255c91583950886a89c3c9adc39a32f0
Reviewed-on: https://go-review.googlesource.com/c/go/+/265124
Trust: Austin Clements <austin@google.com>
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Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Paul Murphy <murp@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
sysMemStats are updated early on in runtime initialization, so
triggering a stack growth would be bad. Mark them nosplit.
Thank you so much to cherryyz@google.com for finding this fix!
Fixes#42218.
Change-Id: Ic62db76e6a4f829355d7eaabed1727c51adfbd0f
Reviewed-on: https://go-review.googlesource.com/c/go/+/265157
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
When a function with non-zero frame size makes a return jump
(RET target), it assembles to, conceptually,
MOV (SP), LR
ADD $framesize, SP
JMP target
We did not clear some fields in the first instruction's Prog.To,
causing it printed like (on ARM)
MOVW.P 4(R13), (R14)(R14)(REG)
Clear the fields to make it print nicer.
Change-Id: I180901aeea41f1ff287d7c6034a6d69005927744
Reviewed-on: https://go-review.googlesource.com/c/go/+/264343
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
This change adds three new metrics: the heap goal, GC cycle count, and
forced GC count. These metrics are identical to their MemStats
counterparts.
For #37112.
Change-Id: I5a5e8dd550c0d646e5dcdbdf38274895e27cdd88
Reviewed-on: https://go-review.googlesource.com/c/go/+/247044
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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For #37112.
Change-Id: Idd3dd5c84215ddd1ab05c2e76e848aa0a4d40fb0
Reviewed-on: https://go-review.googlesource.com/c/go/+/247043
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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This change adds a new benchmark to the runtime tests for measuring the
latency of the new metrics implementation, based on the
ReadMemStats latency benchmark. readMetrics will have more metrics added
to it in the future, and this benchmark will serve as a way to measure
the cost of adding additional metrics.
Change-Id: Ib05e3ed4afa49a70863fc0c418eab35b72263e24
Reviewed-on: https://go-review.googlesource.com/c/go/+/247042
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This change adds support for a variety of runtime memory metrics and
contains the base implementation of Read for the runtime/metrics
package, which lives in the runtime.
It also adds testing infrastructure for the metrics package, and a bunch
of format and documentation tests.
For #37112.
Change-Id: I16a2c4781eeeb2de0abcb045c15105f1210e2d8a
Reviewed-on: https://go-review.googlesource.com/c/go/+/247041
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This change moves the mcache-local malloc stats into the
consistentHeapStats structure so the malloc stats can be managed
consistently with the memory stats. The one exception here is
tinyAllocs for which moving that into the global stats would incur
several atomic writes on the fast path. Microbenchmarks for just one CPU
core have shown a 50% loss in throughput. Since tiny allocation counnt
isn't exposed anyway and is always blindly added to both allocs and
frees, let that stay inconsistent and flush the tiny allocation count
every so often.
Change-Id: I2a4b75f209c0e659b9c0db081a3287bf227c10ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/247039
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This change replaces stacks_inuse, gcWorkBufInUse and
gcProgPtrScalarBitsInUse with their corresponding consistent stats. It
also adds checks to make sure the rest of the sharded stats line up with
existing stats in updatememstats.
Change-Id: I17d0bd181aedb5c55e09c8dff18cef5b2a3a14e3
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This change adds a global set of heap statistics which are similar
to existing memory statistics. The purpose of these new statistics
is to be able to read them and get a consistent result without stopping
the world. The goal is to eventually replace as many of the existing
memstats statistics with the sharded ones as possible.
The consistent memory statistics use a tailor-made synchronization
mechanism to allow writers (allocators) to proceed with minimal
synchronization by using a sequence counter and a global generation
counter to determine which set of statistics to update. Readers
increment the global generation counter to effectively grab a snapshot
of the statistics, and then iterate over all Ps using the sequence
counter to ensure that they may safely read the snapshotted statistics.
To keep statistics fresh, the reader also has a responsibility to merge
sets of statistics.
These consistent statistics are computed, but otherwise unused for now.
Upcoming changes will integrate them with the rest of the codebase and
will begin to phase out existing statistics.
Change-Id: I637a11f2439e2049d7dccb8650c5d82500733ca5
Reviewed-on: https://go-review.googlesource.com/c/go/+/247037
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This change creates the runtime/metrics package and adds the initial
interface as laid out in the design document.
For #37112.
Change-Id: I202dcee08ab008dd63bf96f7a4162f5b5f813637
Reviewed-on: https://go-review.googlesource.com/c/go/+/247040
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This change adds a function getMCache which returns the current P's
mcache if it's available, and otherwise tries to get mcache0 if we're
bootstrapping. This function will come in handy as we need to replicate
this behavior in multiple places in future changes.
Change-Id: I536073d6f6dc6c6390269e613ead9f8bcb6e7f98
Reviewed-on: https://go-review.googlesource.com/c/go/+/246976
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memstats.heap_alloc is 100% a duplicate and unnecessary copy of
memstats.alloc which exists because MemStats used to be populated from
memstats via a memmove.
Change-Id: I995489f61be39786e573b8494a8ab6d4ea8bed9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/246975
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This statistic is updated in many places but for MemStats may be
computed from existing statistics. Specifically by definition
heap_idle = heap_sys - heap_inuse since heap_sys is all memory allocated
from the OS for use in the heap minus memory used for non-heap purposes.
heap_idle is almost the same (since it explicitly includes memory that
*could* be used for non-heap purposes) but also doesn't include memory
that's actually used to hold heap objects.
Although it has some utility as a sanity check, it complicates
accounting and we want fewer, orthogonal statistics for upcoming metrics
changes, so just drop it.
Change-Id: I40af54a38e335f43249f6e218f35088bfd4380d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/246974
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This change breaks apart gc_sys into three distinct pieces. Two of those
pieces are pieces which come from heap_sys since they're allocated from
the page heap. The rest comes from memory mapped from e.g.
persistentalloc which better fits the purpose of a sysMemStat. Also,
rename gc_sys to gcMiscSys.
Change-Id: I098789170052511e7b31edbcdc9a53e5c24573f7
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Currently MemStats is populated via an unsafe memmove from memstats, but
this places unnecessary structural restrictions on memstats, is annoying
to reason about, and tightly couples the two. Instead, just populate the
fields of MemStats explicitly.
Change-Id: I96f6a64326b1a91d4084e7b30169a4bbe6a331f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/246972
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This change modifies the type of several mstats fields to be a new type:
sysMemStat. This type has the same structure as the fields used to have.
The purpose of this change is to make it very clear which stats may be
used in various functions for accounting (usually the platform-specific
sys* functions, but there are others). Currently there's an implicit
understanding that the *uint64 value passed to these functions is some
kind of statistic whose value is atomically managed. This understanding
isn't inherently problematic, but we're about to change how some stats
(which currently use mSysStatInc and mSysStatDec) work, so we want to
make it very clear what the various requirements are around "sysStat".
This change also removes mSysStatInc and mSysStatDec in favor of a
method on sysMemStat. Note that those two functions were originally
written the way they were because atomic 64-bit adds required a valid G
on ARM, but this hasn't been the case for a very long time (since
golang.org/cl/14204, but even before then it wasn't clear if mutexes
required a valid G anymore). Today we implement 64-bit adds on ARM with
a spinlock table.
Change-Id: I4e9b37cf14afc2ae20cf736e874eb0064af086d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/246971
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This change modifies mheap's span allocation API to have each caller
declare a purpose, defined as a new enum called spanAllocType.
The purpose behind this change is two-fold:
1. Tight control over who gets to allocate heap memory is, generally
speaking, a good thing. Every codepath that allocates heap memory
places additional implicit restrictions on the allocator. A notable
example of a restriction is work bufs coming from heap memory: write
barriers are not allowed in allocation paths because then we could
have a situation where the allocator calls into the allocator.
2. Memory statistic updating is explicit. Instead of passing an opaque
pointer for statistic updating, which places restrictions on how that
statistic may be updated, we use the spanAllocType to determine which
statistic to update and how.
We also take this opportunity to group all the statistic updating code
together, which should make the accounting code a little easier to
follow.
Change-Id: Ic0b0898959ba2a776f67122f0e36c9d7d60e3085
Reviewed-on: https://go-review.googlesource.com/c/go/+/246970
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This change renames a bunch of malloc statistics stored in the mcache
that are all named with the "local_" prefix. It also renames largeAlloc
to allocLarge to prevent a naming conflict, and next_sample because it
would be the last mcache field with the old C naming style.
Change-Id: I29695cb83b397a435ede7e9ad5c3c9be72767ea3
Reviewed-on: https://go-review.googlesource.com/c/go/+/246969
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Now that local_scan is the last mcache-based statistic that is flushed
by purgecachedstats, and heap_scan and gcController.revise may be
interacted with concurrently, we don't need to flush heap_scan at
arbitrary locations where the heap is locked, and we don't need
purgecachedstats and cachestats anymore. Instead, we can flush
local_scan at the same time we update heap_live in refill, so the two
updates may share the same revise call.
Clean up unused functions, remove code that would cause the heap to get
locked in the allocSpan when it didn't need to (other than to flush
local_scan), and flush local_scan explicitly in a few important places.
Notably we need to flush local_scan whenever we flush the other stats,
but it doesn't need to be donated anywhere, so have releaseAll do the
flushing. Also, we need to flush local_scan before we set heap_scan at
the end of a GC, which was previously handled by cachestats. Just do so
explicitly -- it's not much code and it becomes a lot more clear why we
need to do so.
Change-Id: I35ac081784df7744d515479896a41d530653692d
Reviewed-on: https://go-review.googlesource.com/c/go/+/246968
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This change makes local_tinyallocs work like the rest of the malloc
stats and doesn't flush local_tinyallocs, instead making that the
source-of-truth.
Change-Id: I3e6cb5f1b3d086e432ce7d456895511a48e3617a
Reviewed-on: https://go-review.googlesource.com/c/go/+/246967
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This change removes mcentral.nmalloc and adds mcache.local_nsmallalloc
which fulfills the same role but may be accessed non-atomically. It also
moves responsibility for updating heap_live and local_nsmallalloc into
mcache functions.
As a result of this change, mcache is now the sole source-of-truth for
malloc stats. It is also solely responsible for updating heap_live and
performing the various operations required as a result of updating
heap_live. The overall improvement here is in code organization:
previously malloc stats were fairly scattered, and now they have one
single home, and nearly all the required manipulations exist in a single
file.
Change-Id: I7e93fa297c1debf17e3f2a0d68aeed28a9c6af00
Reviewed-on: https://go-review.googlesource.com/c/go/+/246966
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This change makes nlargealloc and largealloc into mcache fields just
like nlargefree and largefree. These local fields become the new
source-of-truth. This change also moves the accounting for these fields
out of allocSpan (which is an inappropriate place for it -- this
accounting generally happens much closer to the point of allocation) and
into largeAlloc. This move is partially possible now that we can call
gcController.revise at that point.
Furthermore, this change moves largeAlloc into mcache.go and makes it a
method of mcache. While there's a little bit of a mismatch here because
largeAlloc barely interacts with the mcache, it helps solidify the
mcache as the first allocation layer and provides a clear place to
aggregate and manage statistics.
Change-Id: I37b5e648710733bb4c04430b71e96700e438587a
Reviewed-on: https://go-review.googlesource.com/c/go/+/246965
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This change makes it so that various local malloc stats (excluding
heap_scan and local_tinyallocs) are no longer written first to mheap
fields but are instead accessed directly from each mcache.
This change is part of a move toward having stats be distributed, and
cleaning up some old code related to the stats.
Note that because there's no central source-of-truth, when an mcache
dies, it must donate its stats to another mcache. It's always safe to
donate to the mcache for the 0th P, so do that.
Change-Id: I2556093dbc27357cb9621c9b97671f3c00aa1173
Reviewed-on: https://go-review.googlesource.com/c/go/+/246964
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This change makes it so that the GC assist ratio (the pair of
gcControllerState fields assistBytesPerWork and assistWorkPerByte) is
updated atomically. Note that the pair of fields are not updated
together atomically, but that's OK. The code here was already racy for
some time and in practice the assist ratio moves very slowly.
The purpose of this change is so that we can document
gcController.revise to be safe for concurrent use, which will be useful
in further changes.
Change-Id: Ie25d630207c88e4f85f2b8953f6a0051ebf1b4ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/246963
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