bug fix to encode_arm64.s: some registers overwritten in memmove call #56
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
In encode_arm64.s, encodeBlock, two of the registers added during the port from amd64 were not saved or restored for the memmove call. Instead of saving them, just recalculate their values. Additionally, I made a few small changes to improve things since I've learned a bit more about ARMv8 assembly. - The CMP instruction accepts an immediate as the first argument - use LDP/STP instead of SIMD instructions The change to use the load-pair and store-pair instructions instead of the SIMD instructions results in some modest performance improvements as meastured on Neoverse N1 (Graviton 2). name old time/op new time/op delta WordsDecode1e1-2 25.9ns ± 1% 26.1ns ± 1% +0.66% (p=0.005 n=10+10) WordsDecode1e2-2 107ns ± 0% 105ns ± 0% -1.87% (p=0.000 n=10+10) WordsDecode1e3-2 953ns ± 0% 901ns ± 0% -5.50% (p=0.000 n=10+10) WordsDecode1e4-2 10.6µs ± 0% 9.9µs ± 2% -6.60% (p=0.000 n=7+10) WordsDecode1e5-2 170µs ± 1% 164µs ± 1% -3.12% (p=0.000 n=10+9) WordsDecode1e6-2 1.71ms ± 0% 1.66ms ± 0% -2.98% (p=0.000 n=10+10) WordsEncode1e1-2 22.0ns ± 1% 21.9ns ± 1% -0.67% (p=0.006 n=8+10) WordsEncode1e2-2 248ns ± 0% 245ns ± 0% -1.21% (p=0.002 n=8+10) WordsEncode1e3-2 2.50µs ± 0% 2.49µs ± 0% ~ (p=0.103 n=10+9) WordsEncode1e4-2 27.8µs ± 3% 28.0µs ± 2% ~ (p=0.075 n=10+10) WordsEncode1e5-2 339µs ± 0% 343µs ± 0% +1.18% (p=0.000 n=9+10) WordsEncode1e6-2 3.39ms ± 0% 3.42ms ± 0% +0.94% (p=0.000 n=10+10) RandomEncode-2 74.8µs ± 1% 77.1µs ± 1% +3.16% (p=0.000 n=10+10) _UFlat0-2 68.8µs ± 1% 66.4µs ± 2% -3.54% (p=0.000 n=10+10) _UFlat1-2 770µs ± 0% 740µs ± 1% -3.93% (p=0.000 n=10+10) _UFlat2-2 6.57µs ± 0% 6.55µs ± 0% -0.25% (p=0.000 n=8+10) _UFlat3-2 183ns ± 0% 178ns ± 1% -2.84% (p=0.000 n=9+10) _UFlat4-2 9.76µs ± 1% 9.56µs ± 0% -2.07% (p=0.000 n=10+9) _UFlat5-2 301µs ± 0% 293µs ± 0% -2.67% (p=0.000 n=9+10) _UFlat6-2 280µs ± 1% 267µs ± 1% -4.63% (p=0.000 n=10+10) _UFlat7-2 241µs ± 0% 230µs ± 1% -4.68% (p=0.000 n=9+10) _UFlat8-2 745µs ± 0% 715µs ± 1% -4.11% (p=0.000 n=10+10) _UFlat9-2 1.01ms ± 0% 0.96ms ± 0% -4.60% (p=0.000 n=10+10) _UFlat10-2 62.3µs ± 1% 59.3µs ± 1% -4.72% (p=0.000 n=10+9) _UFlat11-2 258µs ± 0% 252µs ± 1% -2.56% (p=0.000 n=10+10) _ZFlat0-2 135µs ± 1% 132µs ± 1% -1.88% (p=0.000 n=10+8) _ZFlat1-2 1.76ms ± 0% 1.74ms ± 0% -1.00% (p=0.000 n=9+9) _ZFlat2-2 9.54µs ± 0% 9.84µs ± 5% +3.18% (p=0.000 n=10+10) _ZFlat3-2 449ns ± 0% 447ns ± 0% -0.38% (p=0.000 n=10+9) _ZFlat4-2 15.6µs ± 0% 16.0µs ± 4% ~ (p=0.118 n=9+10) _ZFlat5-2 560µs ± 1% 555µs ± 1% -0.89% (p=0.000 n=9+9) _ZFlat6-2 531µs ± 0% 534µs ± 0% +0.64% (p=0.000 n=10+10) _ZFlat7-2 466µs ± 0% 468µs ± 0% +0.32% (p=0.003 n=10+10) _ZFlat8-2 1.42ms ± 0% 1.42ms ± 0% +0.43% (p=0.000 n=10+10) _ZFlat9-2 1.93ms ± 0% 1.94ms ± 0% +0.44% (p=0.000 n=10+10) _ZFlat10-2 120µs ± 0% 121µs ± 3% ~ (p=0.436 n=9+9) _ZFlat11-2 433µs ± 0% 437µs ± 0% +1.03% (p=0.000 n=10+10) ExtendMatch-2 9.77µs ± 0% 9.76µs ± 0% -0.13% (p=0.050 n=10+10) As measured on Cortex-A53 (Raspberry Pi 3) name old time/op new time/op delta WordsDecode1e1-4 152ns ± 2% 151ns ± 0% ~ (p=0.536 n=10+8) WordsDecode1e2-4 639ns ± 0% 617ns ± 0% -3.54% (p=0.000 n=9+8) WordsDecode1e3-4 6.74µs ± 2% 6.35µs ± 0% -5.75% (p=0.000 n=10+9) WordsDecode1e4-4 66.7µs ± 0% 63.5µs ± 0% -4.69% (p=0.000 n=9+9) WordsDecode1e5-4 715µs ± 0% 684µs ± 0% -4.38% (p=0.000 n=8+8) WordsDecode1e6-4 6.87ms ± 2% 6.53ms ± 1% -4.99% (p=0.000 n=10+9) WordsEncode1e1-4 127ns ± 2% 126ns ± 0% ~ (p=0.065 n=10+9) WordsEncode1e2-4 1.58µs ± 0% 1.57µs ± 0% -0.99% (p=0.000 n=8+8) WordsEncode1e3-4 15.1µs ± 0% 14.9µs ± 0% -1.46% (p=0.000 n=9+8) WordsEncode1e4-4 148µs ± 0% 148µs ± 4% ~ (p=0.497 n=9+10) WordsEncode1e5-4 1.54ms ± 0% 1.54ms ± 0% +0.12% (p=0.012 n=10+8) WordsEncode1e6-4 14.4ms ± 0% 14.4ms ± 1% -0.47% (p=0.015 n=9+8) RandomEncode-4 1.13ms ± 1% 1.13ms ± 1% ~ (p=0.529 n=10+10) _UFlat0-4 294µs ± 0% 288µs ± 1% -2.08% (p=0.000 n=9+9) _UFlat1-4 3.05ms ± 1% 2.98ms ± 1% -2.22% (p=0.000 n=9+9) _UFlat2-4 37.3µs ± 0% 37.4µs ± 1% ~ (p=0.093 n=8+9) _UFlat3-4 909ns ± 0% 914ns ± 2% ~ (p=0.526 n=8+10) _UFlat4-4 58.7µs ± 0% 58.1µs ± 0% -1.09% (p=0.000 n=8+10) _UFlat5-4 1.22ms ± 0% 1.19ms ± 1% -2.14% (p=0.000 n=8+8) _UFlat6-4 1.03ms ± 0% 0.99ms ± 0% -3.28% (p=0.000 n=9+8) _UFlat7-4 895µs ± 0% 861µs ± 0% -3.79% (p=0.000 n=8+8) _UFlat8-4 2.83ms ± 0% 2.75ms ± 0% -2.88% (p=0.000 n=7+8) _UFlat9-4 3.85ms ± 1% 3.73ms ± 1% -3.03% (p=0.000 n=8+9) _UFlat10-4 286µs ± 0% 282µs ± 0% -1.59% (p=0.000 n=9+9) _UFlat11-4 1.06ms ± 0% 1.02ms ± 0% -3.58% (p=0.000 n=8+9) _ZFlat0-4 620µs ± 0% 620µs ± 1% ~ (p=0.963 n=9+8) _ZFlat1-4 9.49ms ± 1% 9.67ms ± 3% +1.87% (p=0.000 n=9+10) _ZFlat2-4 61.8µs ± 0% 62.3µs ± 3% ~ (p=0.829 n=8+10) _ZFlat3-4 2.80µs ± 1% 2.79µs ± 0% -0.55% (p=0.000 n=8+8) _ZFlat4-4 108µs ± 0% 109µs ± 0% +0.55% (p=0.000 n=10+8) _ZFlat5-4 2.59ms ± 2% 2.58ms ± 1% ~ (p=0.274 n=10+8) _ZFlat6-4 2.39ms ± 3% 2.40ms ± 1% ~ (p=0.631 n=10+10) _ZFlat7-4 2.11ms ± 0% 2.08ms ± 1% -1.23% (p=0.000 n=10+9) _ZFlat8-4 6.86ms ± 0% 6.92ms ± 1% +0.78% (p=0.000 n=9+8) _ZFlat9-4 9.42ms ± 0% 9.40ms ± 1% ~ (p=0.606 n=8+9) _ZFlat10-4 620µs ± 1% 621µs ± 4% ~ (p=0.173 n=8+10) _ZFlat11-4 1.94ms ± 0% 1.93ms ± 0% -0.52% (p=0.001 n=9+8) ExtendMatch-4 69.3µs ± 2% 69.2µs ± 0% ~ (p=0.515 n=10+8)
|
@nigeltao The change to the Go compiler has now been merged and will expose this bug in snappy if we don't merge this fix. Can you take a look or refer someone who can? Thanks! |
sykesm
added a commit
to sykesm/fabric
that referenced
this pull request
Feb 15, 2021
See golang/snappy#56 Signed-off-by: Matthew Sykes <[email protected]>
sykesm
added a commit
to sykesm/fabric
that referenced
this pull request
Feb 16, 2021
See golang/snappy#56 Signed-off-by: Matthew Sykes <[email protected]>
mastersingh24
pushed a commit
to hyperledger/fabric
that referenced
this pull request
Feb 16, 2021
See golang/snappy#56 Signed-off-by: Matthew Sykes <[email protected]>
|
Should there be a test for this? The following does the trick, but there's probably a smaller input: snappy.Encode(nil, []byte{0xa, 0x5c, 0xa, 0x17, 0xa, 0x8, 0x5f, 0x5f, 0x6e, 0x61, 0x6d, 0x65, 0x5f, 0x5f, 0x12, 0xb, 0x4d, 0x61, 0x74, 0x63, 0x68, 0x53, 0x65, 0x72, 0x69, 0x65, 0x73, 0xa, 0xf, 0xa, 0x2, 0x64, 0x62, 0x12, 0x9, 0x54, 0x65, 0x6e, 0x4d, 0x69, 0x6e, 0x75, 0x74, 0x65, 0xa, 0x13, 0xa, 0xb, 0x54, 0x75, 0x72, 0x62, 0x69, 0x6e, 0x65, 0x54, 0x79, 0x70, 0x65, 0x12, 0x4, 0x56, 0x31, 0x31, 0x32, 0xa, 0x9, 0xa, 0x4, 0x50, 0x61, 0x72, 0x6b, 0x12, 0x1, 0x31, 0x12, 0x10, 0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf0, 0x3f, 0x10, 0xb5, 0xaf, 0xdc, 0xf6, 0xfa, 0x2e, 0xa, 0x5c, 0xa, 0x17, 0xa, 0x8, 0x5f, 0x5f, 0x6e, 0x61, 0x6d, 0x65, 0x5f, 0x5f, 0x12, 0xb, 0x4d, 0x61, 0x74, 0x63, 0x68, 0x53, 0x65, 0x72, 0x69, 0x65, 0x73, 0xa, 0xf, 0xa, 0x2, 0x64, 0x62, 0x12, 0x9, 0x54, 0x65, 0x6e, 0x4d, 0x69, 0x6e, 0x75, 0x74, 0x65, 0xa, 0x13, 0xa, 0xb, 0x54, 0x75, 0x72, 0x62, 0x69, 0x6e, 0x65, 0x54, 0x79, 0x70, 0x65, 0x12, 0x4, 0x56, 0x31, 0x31, 0x32, 0xa, 0x9, 0xa, 0x4, 0x50, 0x61, 0x72, 0x6b, 0x12, 0x1, 0x32, 0x12, 0x10, 0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf0, 0x3f, 0x10, 0xb5, 0xaf, 0xdc, 0xf6, 0xfa, 0x2e, 0xa, 0x5c, 0xa, 0x17, 0xa, 0x8, 0x5f, 0x5f, 0x6e, 0x61, 0x6d, 0x65, 0x5f, 0x5f, 0x12, 0xb, 0x4d, 0x61, 0x74, 0x63, 0x68, 0x53, 0x65, 0x72, 0x69, 0x65, 0x73, 0xa, 0xf, 0xa, 0x2, 0x64, 0x62, 0x12, 0x9, 0x54, 0x65, 0x6e, 0x4d, 0x69, 0x6e, 0x75, 0x74, 0x65, 0xa, 0x13, 0xa, 0xb, 0x54, 0x75, 0x72, 0x62, 0x69, 0x6e, 0x65, 0x54, 0x79, 0x70, 0x65, 0x12, 0x4, 0x56, 0x31, 0x31, 0x32, 0xa, 0x9, 0xa, 0x4, 0x50, 0x61, 0x72, 0x6b, 0x12, 0x1, 0x33, 0x12, 0x10, 0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf0, 0x3f, 0x10, 0xb5, 0xaf, 0xdc, 0xf6, 0xfa, 0x2e, 0xa, 0x5c, 0xa, 0x17, 0xa, 0x8, 0x5f, 0x5f, 0x6e, 0x61, 0x6d, 0x65, 0x5f, 0x5f, 0x12, 0xb, 0x4d, 0x61, 0x74, 0x63, 0x68, 0x53, 0x65, 0x72, 0x69, 0x65, 0x73, 0xa, 0xf, 0xa, 0x2, 0x64, 0x62, 0x12, 0x9, 0x54, 0x65, 0x6e, 0x4d, 0x69, 0x6e, 0x75, 0x74, 0x65, 0xa, 0x13, 0xa, 0xb, 0x54, 0x75, 0x72, 0x62, 0x69, 0x6e, 0x65, 0x54, 0x79, 0x70, 0x65, 0x12, 0x4, 0x56, 0x31, 0x31, 0x32, 0xa, 0x9, 0xa, 0x4, 0x50, 0x61, 0x72, 0x6b, 0x12, 0x1, 0x34, 0x12, 0x10, 0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf0, 0x3f, 0x10, 0xb5, 0xaf, 0xdc, 0xf6, 0xfa, 0x2e})It may be also good to create a new tag now that Go 1.16 is out. |
Done. Sorry for the delay. |
2 tasks
This was referenced Mar 11, 2021
notnoop
pushed a commit
to hashicorp/nomad
that referenced
this pull request
Oct 27, 2021
…11396) Pick up golang/snappy#56 to handle arm64 architectures to fix panics. tldr; Golang 1.16 changed `memmove` implementation for arm64 requiring additional cpu registers that snappy wasn't preserving in its assembly implementation. Other projects have experienced this issue as well, searching for `encode_arm64.s:666` on your favorite search engine will reveal some. Vault updated the dependency earlier this August: hashicorp/vault#12371 . I believe this issue affects Nomad 1.2.x and 1.1.x. Nomad 1.0.x use Golang 1.15 and isn't affected. However, backporting the change to 1.0.x should be harmless. Fixed #11385 .
lgfa29
pushed a commit
to hashicorp/nomad
that referenced
this pull request
Nov 15, 2021
…11396) Pick up golang/snappy#56 to handle arm64 architectures to fix panics. tldr; Golang 1.16 changed `memmove` implementation for arm64 requiring additional cpu registers that snappy wasn't preserving in its assembly implementation. Other projects have experienced this issue as well, searching for `encode_arm64.s:666` on your favorite search engine will reveal some. Vault updated the dependency earlier this August: hashicorp/vault#12371 . I believe this issue affects Nomad 1.2.x and 1.1.x. Nomad 1.0.x use Golang 1.15 and isn't affected. However, backporting the change to 1.0.x should be harmless. Fixed #11385 .
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In an upcoming change to the Go runtime, the memmove function makes use of new registers that exposed this bug. If that change is merged, it will be more important to also merge this change.
This change has passed go-fuzz testing:
In encode_arm64.s, encodeBlock, two of the registers added during the port from
amd64 were not saved or restored for the memmove call. Instead of saving them,
just recalculate their values. Additionally, I made a few small changes to
improve things since I've learned a bit more about ARMv8 assembly.
The change to use the load-pair and store-pair instructions instead of the SIMD
instructions results in some modest performance improvements as meastured on
Neoverse N1 (Graviton 2).