1152836 - WiFi auth scanner is slow

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Developer Tools, defect)

Description

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

At the moment, the QR recognition cycle is extremely long on devices.

On the Flame, it takes roughly 20s to recognize an image.

The current code is not optimized at all.  I have several patches that will bring this down to the 1.5s range.

Comment 1

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: bz://1152836/jryans

/r/6815 - Bug 1152836 - QR Decoder: Cache imagedata.data: 915ms -> 750ms r=past
/r/6817 - Bug 1152836 - QR Decoder: Remove QR namespace (image, h/w): 750ms -> 580ms r=past
/r/6819 - Bug 1152836 - QR Decoder: Let everywhere, style nits: 580ms -> 400ms r=past
/r/6821 - Bug 1152836 - QR Decoder: Remove getPixel bounds check: 400ms -> 335ms r=past
/r/6823 - Bug 1152836 - QR Decoder: Add 32bit buffer: 335ms -> 256ms r=past
/r/6825 - Bug 1152836 - QR Decoder: Grayscale clamped array: 256ms -> 235ms r=past
/r/6827 - Bug 1152836 - QR Decoder: Inline getPixel: 235ms -> 225ms r=past

Pull down these commits:

hg pull -r 2c0d3ca7200fba5b3ec46a8f6c31d5c4b5a20fdf https://reviewboard-hg.mozilla.org/gecko/

Comment 2

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Panos, here a bunch of micro-optimizations for the QR decoder library we used on devices.

On desktop, everything added together brings about 4x improvement (915ms -> 225ms).
On the Flame, it's more like 13x improvement (20000ms -> 1500ms), which make the scanner much more usable!

While toiling in the library, I've seen several other possible optimizations, but these seem like enough to worry about for now.

Comment 3

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=7ccddd0e8232

Comment 4

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6815/#review5727

Ship It!

Comment 5

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6817/#review5729

Ship It!

Comment 6

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6819/#review5731

Ship It!

::: toolkit/devtools/qrcode/decoder/index.js
(Diff revision 1)
> -    return this.errorCorrectionLevel.ordinal() << 3 | dataMask;
> +    return this.errorCorrectionLevel.ordinal() << 3 | this.dataMask;

Whoa!

::: toolkit/devtools/qrcode/decoder/index.js
(Diff revision 1)
> -      var eval = poly.evaluateAt(this.field.exp(dataMatrix ? i + 1 : i));
> -      syndromeCoefficients[syndromeCoefficients.length - 1 - i] = eval;
> -      if (eval != 0) {
> +      let value = poly.evaluateAt(this.field.exp(dataMatrix ? i + 1 : i));
> +      syndromeCoefficients[syndromeCoefficients.length - 1 - i] = value;
> +      if (value !== 0) {

Geez!

Comment 7

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6821/#review5733

Ship It!

Comment 8

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6823/#review5735

Ship It!

Comment 9

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6825/#review5737

Ship It!

Comment 10

[Panos Astithas (he/him) [:past] (please ni?)]

https://reviewboard.mozilla.org/r/6827/#review5739

Ship It!

Comment 11

[Panos Astithas (he/him) [:past] (please ni?)]

Comment on attachment 8590552 [details]
MozReview Request: bz://1152836/jryans

https://reviewboard.mozilla.org/r/6813/#review5741

Nice! I take it we don't expect to pick up changes from upstream very often, right?

Comment 12

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

(In reply to Panos Astithas [:past] from comment #11)
> Comment on attachment 8590552 [details]
> MozReview Request: bz://1152836/jryans
> 
> https://reviewboard.mozilla.org/r/6813/#review5741
> 
> Nice! I take it we don't expect to pick up changes from upstream very often,
> right?

No, the last change was 2014-01-09 (~15 months ago).  It's basically a port of Java code from even longer ago, I think.

So, anyway, I think we are fine to diverge as needed.

Comment 13

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

remote:   https://hg.mozilla.org/integration/fx-team/rev/b71c0a6ffa5e
remote:   https://hg.mozilla.org/integration/fx-team/rev/6e9cea30c62d
remote:   https://hg.mozilla.org/integration/fx-team/rev/169c46b4e35e
remote:   https://hg.mozilla.org/integration/fx-team/rev/f08b4a38f895
remote:   https://hg.mozilla.org/integration/fx-team/rev/d231cf0ff16a
remote:   https://hg.mozilla.org/integration/fx-team/rev/dd707db723cf
remote:   https://hg.mozilla.org/integration/fx-team/rev/61a64147f504

Comment 14

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/b71c0a6ffa5e
https://hg.mozilla.org/mozilla-central/rev/6e9cea30c62d
https://hg.mozilla.org/mozilla-central/rev/169c46b4e35e
https://hg.mozilla.org/mozilla-central/rev/f08b4a38f895
https://hg.mozilla.org/mozilla-central/rev/d231cf0ff16a
https://hg.mozilla.org/mozilla-central/rev/dd707db723cf
https://hg.mozilla.org/mozilla-central/rev/61a64147f504

Comment 16

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Remove QR namespace (image, h/w): 750ms -> 580ms r=past

Comment 17

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Let everywhere, style nits: 580ms -> 400ms r=past

Comment 18

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Remove getPixel bounds check: 400ms -> 335ms r=past

Comment 19

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Add 32bit buffer: 335ms -> 256ms r=past

Comment 20

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Grayscale clamped array: 256ms -> 235ms r=past

Comment 21

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Inline getPixel: 235ms -> 225ms r=past

Comment 22

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Attachment: MozReview Request: Bug 1152836 - QR Decoder: Cache imagedata.data: 915ms -> 750ms r=past