On Haswell I measure anywhere between 2X to 3.5X speedup for RSA.
I believe other architectures will also greatly improve.
In the future may be upgraded by dedicated assembly routine.
Built-in benchmarks i5-4278U turbo off:
benchmark old ns/op new ns/op delta
BenchmarkRSA2048Decrypt 6696649 3073769 -54.10%
Benchmark3PrimeRSA2048Decrypt 4472340 1669080 -62.68%
Change-Id: I17df84f85e34208f990665f9f90ea671695b2add
Reviewed-on: https://go-review.googlesource.com/9253
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Vlad Krasnov <vlad@cloudflare.com>
Run-TryBot: Adam Langley <agl@golang.org>
Given a call frame F of size N where the return values start at offset R,
callwritebarrier was instructing heapBitsBulkBarrier to scan the block
of memory [F+R, F+R+N). It should only scan [F+R, F+N). The extra N-R
bytes scanned might lead into the next allocated block in memory.
Because the scan was consulting the heap bitmap for type information,
scanning into the next block normally "just worked" in the sense of
not crashing.
Scanning the extra N-R bytes of memory is a problem mainly because
it causes the GC to consider pointers that might otherwise not be
considered, leading it to retain objects that should actually be freed.
This is very difficult to detect.
Luckily, juju turned up a case where the heap bitmap and the memory
were out of sync for the block immediately after the call frame, so that
heapBitsBulkBarrier saw an obvious non-pointer where it expected a
pointer, causing a loud crash.
Why is there a non-pointer in memory that the heap bitmap records as
a pointer? That is more difficult to answer. At least one way that it
could happen is that allocations containing no pointers at all do not
update the heap bitmap. So if heapBitsBulkBarrier walked out of the
current object and into a no-pointer object and consulted those bitmap
bits, it would be misled. This doesn't happen in general because all
the paths to heapBitsBulkBarrier first check for the no-pointer case.
This may or may not be what happened, but it's the only scenario
I've been able to construct.
I tried for quite a while to write a simple test for this and could not.
It does fix the juju crash, and it is clearly an improvement over the
old code.
Fixes#10844.
Change-Id: I53982c93ef23ef93155c4086bbd95a4c4fdaac9a
Reviewed-on: https://go-review.googlesource.com/10317
Reviewed-by: Austin Clements <austin@google.com>
F3t was effectively a local variable.
Remove it.
This shrinks obj.Prog from 456 to 448 bytes,
which places it in a smaller malloc class.
This reduces the memory usage of the compiler
while compiling the rotate tests by ~2.75%.
Change-Id: I31cc9dd67269851a430b56bcc7d255c9349eb522
Reviewed-on: https://go-review.googlesource.com/10255
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Without this, they install to $GOROOT/bin.
Change-Id: Iae4b8f59c8392f6abd841490e56922738089f8d4
Reviewed-on: https://go-review.googlesource.com/10297
Reviewed-by: Russ Cox <rsc@golang.org>
This CL removes the remaining visible uses of the "architecture letter" concept.
(They are no longer in tool names nor in source directory names.)
Because the architecture letter concept is now gone, delete GOCHAR
from "go env" output, and change go/build.ArchChar to return an
error always.
The architecture letter is still used in the compiler and linker sources
as a clumsy architecture enumeration, but that use is not visible to
Go users and can be cleaned up separately.
Change-Id: I4d97a38f372003fb610c9c5241bea440d9dbeb8d
Reviewed-on: https://go-review.googlesource.com/10289
Reviewed-by: Rob Pike <r@golang.org>
This CL fixes the build to use the newly created go tool compile
and go tool link in place of go tool 5g, go tool 5l, and so on.
See golang-dev thread titled "go tool compile, etc" for background.
Although it was not a primary motivation, this conversion does
reduce the wall clock time and cpu time required for make.bash
by about 10%.
Change-Id: I79cbbdb676cab029db8aeefb99a53178ff55f98d
Reviewed-on: https://go-review.googlesource.com/10288
Reviewed-by: Rob Pike <r@golang.org>
Trivial merging of 5g, 6g, ... into go tool compile,
and similarlly 5l, 6l, ... into go tool link.
The files compile/main.go and link/main.go are new.
Everything else in those directories is a move followed by
change of imports and package name.
This CL breaks the build. Manual fixups are in the next CL.
See golang-dev thread titled "go tool compile, etc" for background.
Change-Id: Id35ff5a5859ad9037c61275d637b1bd51df6828b
Reviewed-on: https://go-review.googlesource.com/10287
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Rob Pike <r@golang.org>
In preparation for making the current linker cmd/link.
If cmd/newlink is ever completed, it can be moved back.
See golang-dev thread titled "go tool compile, etc" for background.
Change-Id: I4029580f470038240c5181a37ea4202ba971f9ef
Reviewed-on: https://go-review.googlesource.com/10286
Reviewed-by: Rob Pike <r@golang.org>
Currently runtime.callers invokes gentraceback with the pc and sp of
the G it is called from, but always passes g0 even if it was called
from a regular g. Right now this has no ill effects because
runtime.callers does not use either callback argument or the
_TraceJumpStack flag, but it makes the code fragile and will break
some upcoming changes.
Fix this by lifting the getg() call outside of the systemstack in
runtime.callers.
Change-Id: I4e1e927961c0e0cd4dcf28693be47df7bae9e122
Reviewed-on: https://go-review.googlesource.com/10292
Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
Also mentions golang.org/x/net/ipv4 and golang.org/x/net/ipv6.
Change-Id: I653deac7a5e2b129237655a72d6c91207f1b1685
Reviewed-on: https://go-review.googlesource.com/9779
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Formerly it would return a BadExpr.
This prevents partial syntax from being discarded, and makes the error
recovery logic more consistent with other places where an identifier
was expected but not found.
+ test
Change-Id: I223c0c0589e7ceb7207ae951b8f71b9275a1eb73
Reviewed-on: https://go-review.googlesource.com/10269
Reviewed-by: Robert Griesemer <gri@golang.org>
An error in string slice offsets caused the loop to run forever if the
first character in the argument was a period.
Fixes#10833.
Change-Id: Iefb6aac5cff8864fe93d08e2600cb07d82c6f6df
Reviewed-on: https://go-review.googlesource.com/10285
Reviewed-by: Russ Cox <rsc@golang.org>
This is dead code. If you want to quiesce the system the
preferred way is to use forEachP(func(*p){}).
Change-Id: Ic7677a5dd55e3639b99e78ddeb2c71dd1dd091fa
Reviewed-on: https://go-review.googlesource.com/10267
Reviewed-by: Austin Clements <austin@google.com>
Makes little difference internally but makes go list output more useful.
Change-Id: I1fa1f839107de08818427382b2aef8dc4d765b36
Reviewed-on: https://go-review.googlesource.com/10192
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
On Windows, we need to make sure that the node under test has external
connectivity.
Fixes#10795.
Change-Id: I99f2336180c7b56474fa90a4a6cdd5a6c4dd3805
Reviewed-on: https://go-review.googlesource.com/10006
Reviewed-by: Ian Lance Taylor <iant@golang.org>
On my systems, ld -rpath sets DT_RUNPATH instead of DT_RPATH.
Change-Id: I5047e795fb7ef9336f5fa13ba24bb6245c0b0582
Reviewed-on: https://go-review.googlesource.com/10260
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
386 is not affected because it doesn't use ginscmp.
Fixes#10843.
Change-Id: I1b3a133bd1e5fabc85236f15d060dbaa4c391cf3
Reviewed-on: https://go-review.googlesource.com/10116
Reviewed-by: Russ Cox <rsc@golang.org>
In css, js, and html, the replacement operations are implemented
by iterating on strings (rune by rune). The for/range
statement is used. The length of the rune is required
and added to the index to properly slice the string.
This is potentially wrong because there is a discrepancy between
the result of utf8.RuneLen and the increment of the index
(set by the for/range statement). For invalid strings,
utf8.RuneLen('\ufffd') == 3, while the index is incremented
only by 1 byte.
htmlReplacer triggers a panic at slicing time for some
invalid strings.
Use a more robust iteration mechanism based on
utf8.DecodeRuneInString, and make sure the same
pattern is used for all similar functions in this
package.
Fixes#10799
Change-Id: Ibad3857b2819435d9fa564f06fc2ca8774102841
Reviewed-on: https://go-review.googlesource.com/10105
Reviewed-by: Rob Pike <r@golang.org>
Commit 9c9e36b pushed these errors down to where the write barriers
are actually emitted, but forgot to remove the original error that was
being pushed down.
Change-Id: I751752a896e78fb9e63d69f88e7fb8d1ff5d344c
Reviewed-on: https://go-review.googlesource.com/10264
Reviewed-by: Russ Cox <rsc@golang.org>
The existing implementation executes `gofmt` binary from PATH
environment variable on invocation `go fmt` command.
Relying on PATH might lead to confusions for users with several Go installations.
It's more appropriate to run `gofmt` from GOBIN (if defined) or GOROOT.
Fixes#10755
Change-Id: I56d42a747319c766f2911508fab3994c3a366d12
Reviewed-on: https://go-review.googlesource.com/9900
Reviewed-by: Rob Pike <r@golang.org>
Prior to this CL whenever the GC marking was enabled and
a P was looking for work we supplied a G to help
the GC do its marking tasks. Once this G finished all
the marking available it would release the P to find another
available G. In the case where there was no work the P would drop
into findrunnable which would execute the mark helper G which would
immediately return and the P would drop into findrunnable again repeating
the process. Since the P was always given a G to run it never blocks.
This CL first checks if the GC mark helper G has available work and if
not the P immediately falls through to its blocking logic.
Fixes#10901
Change-Id: I94ac9646866ba64b7892af358888bc9950de23b5
Reviewed-on: https://go-review.googlesource.com/10189
Reviewed-by: Austin Clements <austin@google.com>
Currently setGCPercent sets heapminimum to heapminimum*GOGC/100. The
real intent is to set heapminimum to a scaled multiple of a fixed
default heap minimum, not to scale heapminimum based on its current
value. This turns out to be okay because setGCPercent is only called
once and heapminimum is initially set to this default heap minimum.
However, the code as written is confusing, especially since
setGCPercent is otherwise written so it could be called again to
change GOGC. Fix this by introducing a defaultHeapMinimum constant and
using this instead of the current value of heapminimum to compute the
scaled heap minimum.
As part of this, this commit improves the documentation on
heapminimum.
Change-Id: I4eb82c73dc2eb44a6e5a17c780a747a2e73d7493
Reviewed-on: https://go-review.googlesource.com/10181
Reviewed-by: Russ Cox <rsc@golang.org>
I think "the flag" was a typo, and the word "after" was repetitive.
Change-Id: I81c034ca11a3a778ff1eb4b3af5b96bc525ab985
Reviewed-on: https://go-review.googlesource.com/10195
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Rearrange Node fields to enable better struct packing.
This reduces readability in favor of shrinking
the size of Nodes.
This reduces the size of Node from 328 to 312.
This reduces the memory usage to compile the
rotate tests by about 4.4%.
No functional changes. Passes toolstash -cmp.
Updates #9933.
Change-Id: I2764c5847fb1635ddc898e2ee385d007d67f03c5
Reviewed-on: https://go-review.googlesource.com/10141
Reviewed-by: Russ Cox <rsc@golang.org>
Param will be converted from an anonymous to a
named field in a subsequent, automated CL.
Reduces Node size from 368 to 328.
Reduces inuse_space on the rotate tests by about 3%.
No functional changes. Passes toolstash -cmp.
Updates #9933.
Change-Id: I5867b00328abf17ee24aea6ca58876bae9d8bfed
Reviewed-on: https://go-review.googlesource.com/10210
Reviewed-by: Russ Cox <rsc@golang.org>
Funcdepth was already int32. Make Escloopdepth
and Decldepth also int32 instead of int.
No functional changes for non-absurd code. Passes toolstash -cmp.
Change-Id: I47e145dd732b6a73cfcc6d45956df0dbccdcd999
Reviewed-on: https://go-review.googlesource.com/10129
Reviewed-by: Russ Cox <rsc@golang.org>
This is a duplicate of CL 9491.
That CL broke the build due to pprof shortcomings
and was reverted in CL 9565.
CL 9623 fixed pprof, so this can go in again.
Fixes#10659.
Change-Id: If470fc90b3db2ade1d161b4417abd2f5c6c330b8
Reviewed-on: https://go-review.googlesource.com/10212
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Better layout.
Fixes#10859.
The issue suggests rearranging so the comment comes out
after the methods. I tried this and it looks good but it is less
useful, since the stuff you're probably looking for - the methods
- are scrolled away by the comment. The most important
information should be last because that leaves it on your
screen after the print if the output is long.
Change-Id: I560f992601ccbe2293c347fa1b1018a3f5346c82
Reviewed-on: https://go-review.googlesource.com/10160
Reviewed-by: Russ Cox <rsc@golang.org>
And fix to work on filesystems with only 1s resolution.
Fixes#10724
Change-Id: Ia07463f090b4290fc27f5953fa94186463d7afc7
Reviewed-on: https://go-review.googlesource.com/9768
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Modified esc.go to allow slice literals (before append)
to be non-escaping. Modified tests to account for changes
in escape behavior and to also test the two cases that
were previously not tested.
Also minor cleanups to debug-printing within esc.go
Allocation stats for running compiler
( cd src/html/template;
for i in {1..5} ; do
go tool 6g -memprofile=testzz.${i}.prof -memprofilerate=1 *.go ;
go tool pprof -alloc_objects -text testzz.${i}.prof ;
done ; )
before about 86k allocations
after about 83k allocations
Fixes#8972
Change-Id: Ib61dd70dc74adb40d6f6fdda6eaa4bf7d83481de
Reviewed-on: https://go-review.googlesource.com/10118
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, forEachP reuses the stopwait and stopnote fields from
stopTheWorld to track how many Ps have not responded to the safe-point
request and to sleep until all Ps have responded.
It was assumed this was safe because both stopTheWorld and forEachP
must occur under the worlsema and hence stopwait and stopnote cannot
be used for both purposes simultaneously and callers could always
determine the appropriate use based on sched.gcwaiting (which is only
set by stopTheWorld). However, this is not the case, since it's
possible for there to be a window between when an M observes that
gcwaiting is set and when it checks stopwait during which stopwait
could have changed meanings. When this happens, the M decrements
stopwait and may wakeup stopnote, but does not otherwise participate
in the forEachP protocol. As a result, stopwait is decremented too
many times, so it may reach zero before all Ps have run the safe-point
function, causing forEachP to wake up early. It will then either
observe that some P has not run the safe-point function and panic with
"P did not run fn", or the remaining P (or Ps) will run the safe-point
function before it wakes up and it will observe that stopwait is
negative and panic with "not stopped".
Fix this problem by giving forEachP its own safePointWait and
safePointNote fields.
One known sequence of events that can cause this race is as
follows. It involves three actors:
G1 is running on M1 on P1. P1 has an empty run queue.
G2/M2 is in a blocked syscall and has lost its P. (The details of this
don't matter, it just needs to be in a position where it needs to grab
an idle P.)
GC just started on G3/M3/P3. (These aren't very involved, they just
have to be separate from the other G's, M's, and P's.)
1. GC calls stopTheWorld(), which sets sched.gcwaiting to 1.
Now G1/M1 begins to enter a syscall:
2. G1/M1 invokes reentersyscall, which sets the P1's status to
_Psyscall.
3. G1/M1's reentersyscall observes gcwaiting != 0 and calls
entersyscall_gcwait.
4. G1/M1's entersyscall_gcwait blocks acquiring sched.lock.
Back on GC:
5. stopTheWorld cas's P1's status to _Pgcstop, does other stuff, and
returns.
6. GC does stuff and then calls startTheWorld().
7. startTheWorld() calls procresize(), which sets P1's status to
_Pidle and puts P1 on the idle list.
Now G2/M2 returns from its syscall and takes over P1:
8. G2/M2 returns from its blocked syscall and gets P1 from the idle
list.
9. G2/M2 acquires P1, which sets P1's status to _Prunning.
10. G2/M2 starts a new syscall and invokes reentersyscall, which sets
P1's status to _Psyscall.
Back on G1/M1:
11. G1/M1 finally acquires sched.lock in entersyscall_gcwait.
At this point, G1/M1 still thinks it's running on P1. P1's status is
_Psyscall, which is consistent with what G1/M1 is doing, but it's
_Psyscall because *G2/M2* put it in to _Psyscall, not G1/M1. This is
basically an ABA race on P1's status.
Because forEachP currently shares stopwait with stopTheWorld. G1/M1's
entersyscall_gcwait observes the non-zero stopwait set by forEachP,
but mistakes it for a stopTheWorld. It cas's P1's status from
_Psyscall (set by G2/M2) to _Pgcstop and proceeds to decrement
stopwait one more time than forEachP was expecting.
Fixes#10618. (See the issue for details on why the above race is safe
when forEachP is not involved.)
Prior to this commit, the command
stress ./runtime.test -test.run TestFutexsleep\|TestGoroutineProfile
would reliably fail after a few hundred runs. With this commit, it
ran for over 2 million runs and never crashed.
Change-Id: I9a91ea20035b34b6e5f07ef135b144115f281f30
Reviewed-on: https://go-review.googlesource.com/10157
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, startTheWorld releases worldsema before starting the
world. Since startTheWorld can change gomaxprocs after allowing Ps to
run, this means that gomaxprocs can change while another P holds
worldsema.
Unfortunately, the garbage collector and forEachP assume that holding
worldsema protects against changes in gomaxprocs (which it *almost*
does). In particular, this is causing somewhat frequent "P did not run
fn" crashes in forEachP in the runtime tests because gomaxprocs is
changing between the several loops that forEachP does over all the Ps.
Fix this by only releasing worldsema after the world is started.
This relates to issue #10618. forEachP still fails under stress
testing, but much less frequently.
Change-Id: I085d627b70cca9ebe9af28fe73b9872f1bb224ff
Reviewed-on: https://go-review.googlesource.com/10156
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, startTheWorld clears preemptoff for the current M before
starting the world. A few callers increment m.locks around
startTheWorld, presumably to prevent preemption any time during
starting the world. This is almost certainly pointless (none of the
other callers do this), but there's no harm in making startTheWorld
keep preemption disabled until it's all done, which definitely lets us
drop these m.locks manipulations.
Change-Id: I8a93658abd0c72276c9bafa3d2c7848a65b4691a
Reviewed-on: https://go-review.googlesource.com/10155
Reviewed-by: Russ Cox <rsc@golang.org>
There are several steps to stopping and starting the world and
currently they're open-coded in several places. The garbage collector
is the only thing that needs to stop and start the world in a
non-trivial pattern. Replace all other uses with calls to higher-level
functions that implement the entire pattern necessary to stop and
start the world.
This is a pure refectoring and should not change any code semantics.
In the following commits, we'll make changes that are easier to do
with this abstraction in place.
This commit renames the old starttheworld to startTheWorldWithSema.
This is a slight misnomer right now because the callers release
worldsema just before calling this. However, a later commit will swap
these and I don't want to think of another name in the mean time.
Change-Id: I5dc97f87b44fb98963c49c777d7053653974c911
Reviewed-on: https://go-review.googlesource.com/10154
Reviewed-by: Russ Cox <rsc@golang.org>
