Bug 235448

Summary:

file.stream() is slow and CPU-bound

Product:

WebKit

Reporter:

Jacob Bandes-Storch <jacob>

Component:

New Bugs

Assignee:

youenn fablet <youennf>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

achristensen, ap, cdumez, webkit-bug-importer, youennf

Priority:

Keywords:

InRadar

Version:

Safari 15

Hardware:

Mac (Apple Silicon)

OS:

macOS 12

Attachments:

Description	Flags
Screen recording demonstrating the issue	none
Patch	none
Patch for landing	none

Jacob Bandes-Storch

Reported 2022-01-21 11:05:13 PST

Created attachment 449672 [details] Screen recording demonstrating the issue Also filed as FB9854642 Reading a file with file.stream() is much slower than repeatedly calling file.slice(). 1. Visit https://jsfiddle.net/0hnembvu/21/ 2. Choose a large file (~200MB). Observe the progress bar updates smoothly, and the file can be read in ~200ms. 3. Reload the page. 4. Enable the "use ReadableStream API" checkbox. 5. Choose the same large file again. Observe the page becomes unresponsive while reading (the progress bar does not update smoothly) and the file takes much longer to read (~1500ms).

Attachments
Screen recording demonstrating the issue (9.40 MB, video/quicktime) 2022-01-21 11:05 PST, Jacob Bandes-Storch	no flags	Details
Patch (5.14 KB, patch) 2022-01-24 10:25 PST, youenn fablet	no flags	Details Formatted Diff Diff
Patch for landing (5.16 KB, patch) 2022-01-24 11:28 PST, youenn fablet	no flags	Details Formatted Diff Diff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.

Jacob Bandes-Storch

Comment 1 2022-01-21 11:37:52 PST

Real world example: https://github.com/foxglove/studio/pull/2711/commits/a1ebf5f13b20348832314d19bab1a522e5b35b8a#diff-b179de6d22a74da74418686ff2da061144a5cd7d814facb743da2b755e17598aR272

Radar WebKit Bug Importer

Comment 2 2022-01-24 10:25:46 PST

<rdar://problem/87977499>

youenn fablet

Comment 3 2022-01-24 10:25:53 PST

Created attachment 449827 [details] Patch

Alex Christensen

Comment 4 2022-01-24 11:22:27 PST

Comment on attachment 449827 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=449827&action=review > Source/WebCore/fileapi/Blob.cpp:273 > return; This is a little strange. There is nothing after this now.

youenn fablet

Comment 5 2022-01-24 11:28:08 PST

Created attachment 449836 [details] Patch for landing

EWS

Comment 6 2022-01-24 13:13:50 PST

Committed r288463 (246349@main): <https://commits.webkit.org/246349@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 449836 [details].

Jacob Bandes-Storch

Comment 7 2022-01-24 14:28:58 PST

Amazing turnaround time! :D

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