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math/big: ppc64 has no assembly implementation of arith.go functions #16621

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izzystardust opened this issue Aug 5, 2016 · 2 comments
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math/big: ppc64 has no assembly implementation of arith.go functions #16621

izzystardust opened this issue Aug 5, 2016 · 2 comments
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FrozenDueToAge Performance
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Go1.8Maybe

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@izzystardust
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Please answer these questions before submitting your issue. Thanks!

  1. What version of Go are you using (go version)?
    go version devel +b882707 Thu Jul 21 15:33:00 2016 -0500 linux/ppc64le
  2. What operating system and processor architecture are you using (go env)?
    linux/ppc64le
  3. What did you do?
    I noticed that performance of crypto/ecdsa on POWER was significantly slower than on Intel, due in large part to time spent in functions in arith.go
  4. What did you expect to see?
    Similar performance profile to Intel.

I have a change that optimizes hotspots in ppc64 assembly.
@bradfitz bradfitz changed the title ppc64 has no assembly implementation of arith.go functions math/big: ppc64 has no assembly implementation of arith.go functions Aug 5, 2016
@bradfitz bradfitz added this to the Go1.8Maybe milestone Aug 5, 2016
@bradfitz
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bradfitz commented Aug 5, 2016

/cc @laboger

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CL https://golang.org/cl/26951 mentions this issue.

ceseo pushed a commit to powertechpreview/go that referenced this issue Dec 1, 2016
@ceseo
math/big: add assembly implementation of arith for ppc64{le}
ae6249c 
The existing implementation used a pure go implementation, leading to slow
cryptographic performance.

Implemented mulWW, subVV, mulAddVWW, addMulVVW, and bitLen for
ppc64{le}.
Implemented divWW for ppc64le only, as the DIVDEU instruction is only
available on Power8 or newer.

benchcmp output:

benchmark                         old ns/op     new ns/op     delta
BenchmarkSignP384                 28934360      10877330      -62.41%
BenchmarkRSA2048Decrypt           41261033      5139930       -87.54%
BenchmarkRSA2048Sign              45231300      7610985       -83.17%
Benchmark3PrimeRSA2048Decrypt     20487300      2481408       -87.89%

Fixes golang#16621

Change-Id: If8b68963bb49909bde832f2bda08a3791c4f5b7a
Reviewed-on: https://go-review.googlesource.com/26951
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
ceseo pushed a commit to powertechpreview/go that referenced this issue Dec 1, 2016
@ceseo
math/big: add assembly implementation of arith for ppc64{le}
e9b04aa 
The existing implementation used a pure go implementation, leading to slow
cryptographic performance.

Implemented mulWW, subVV, mulAddVWW, addMulVVW, and bitLen for
ppc64{le}.
Implemented divWW for ppc64le only, as the DIVDEU instruction is only
available on Power8 or newer.

benchcmp output:

benchmark                         old ns/op     new ns/op     delta
BenchmarkSignP384                 28934360      10877330      -62.41%
BenchmarkRSA2048Decrypt           41261033      5139930       -87.54%
BenchmarkRSA2048Sign              45231300      7610985       -83.17%
Benchmark3PrimeRSA2048Decrypt     20487300      2481408       -87.89%

Fixes golang#16621

Change-Id: If8b68963bb49909bde832f2bda08a3791c4f5b7a
Reviewed-on: https://go-review.googlesource.com/26951
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
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