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Issue 669838 link

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Issue metadata

Status: Fixed
Owner: ----
Closed: Jan 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux
Pri: 2
Type: Bug



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TransformationMatrix::inverse should use multiplication instead of division

Reported by ossy.sze...@gmail.com, Nov 30 2016

Issue description

UserAgent: Mozilla/5.0 (Windows NT 5.1; rv:50.0) Gecko/20100101 Firefox/50.0

Steps to reproduce the problem:
The general (non SIMD optimized) path of TransformationMatrix::inverse now divides 16 matrix elements with the determinant. But multiplication with the reciprocal of the determinant would be much faster, at least on ARM(v7). (The SIMD optimizations already uses this trick too.)

What is the expected behavior?

What went wrong?
nothing

Did this work before? N/A 

Chrome version:   Channel: n/a
OS Version: 
Flash Version:
 

Comment 2 by ajha@chromium.org, Nov 30 2016

Labels: M-57
Cc: hdodda@chromium.org
Labels: Needs-Feedback
@ossy.szeged-- Could you please help us by providing test case to reproduce the issue and also the chrome browser version in which you are facing the issue.

Thanks!
Project Member

Comment 4 by bugdroid1@chromium.org, Dec 7 2016

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97e30b35dd6b89ee97f08cf467c80df5d3369fa5

commit 97e30b35dd6b89ee97f08cf467c80df5d3369fa5
Author: ossy.szeged <ossy.szeged@gmail.com>
Date: Wed Dec 07 11:56:06 2016

TransformationMatrix::inverse should use multiplication instead of division

Microbenchmark: Execute 1 million matrix inversion in a for loop.

Result: (measured on Arndale Octa board - Cortex-A15)
|                            | before(ms)| after(ms) | Speedup |
| GCC 4.8.2                  | 7545      | 2575      | 2.93x   |
| Clang 4.0.0 (trunk 287685) | 8260      | 3555      | 2.32x   |

BUG= 669838 

Review-Url: https://codereview.chromium.org/2545473002
Cr-Commit-Position: refs/heads/master@{#436920}

[modify] https://crrev.com/97e30b35dd6b89ee97f08cf467c80df5d3369fa5/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp

Components: Blink>CSS>CSS3D
Status: Fixed (was: Unconfirmed)

Comment 7 by suzyh@chromium.org, Mar 24 2017

Components: -Blink>CSS>CSS3D Blink>Compositing>Transform3D

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