Bug #2368: sendfile(2) freezes for a few seconds - DragonFlyBSD - DragonFlyBSD bugtracker

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Bug #2368

closed

sendfile(2) freezes for a few seconds

Added by ftigeot over 12 years ago. Updated over 12 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Category:

Target version:

Start date:

05/16/2012

Due date:

% Done:

100%

Estimated time:

Description

Having updated a web server to apache-2.4 (sendfile enabled), I noticed
some static images didn't load in one go:

- top parts are displayed instantly
- image downloads freeze for a few seconds
- missing bottom parts are then downloaded and displayed instantly

Switching EnableSendfile between on/off in httpd.conf enables or disables
this behavior 100% of the time

Files

tcpdump-sendfile.txt (3.88 KB) tcpdump-sendfile.txt

ftigeot, 05/16/2012 11:50 PM

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Updated by sepherosa over 12 years ago

On Thu, May 17, 2012 at 3:07 AM, Francois Tigeot via Redmine
<bugtracker-admin@leaf.dragonflybsd.org> wrote:

Issue #2368 has been reported by Francois Tigeot.

----------------------------------------
Bug #2368: sendfile(2) freezes for a few seconds
http://bugs.dragonflybsd.org/issues/2368

Author: Francois Tigeot
Status: New
Priority: Normal
Assignee:
Category:
Target version:

Having updated a web server to apache-2.4 (sendfile enabled), I noticed
some static images didn't load in one go:

- top parts are displayed instantly
- image downloads freeze for a few seconds
- missing bottom parts are then downloaded and displayed instantly

Switching EnableSendfile between on/off in httpd.conf enables or disables
this behavior 100% of the time

Possible to get a tcpdump (w/ -s 128 should be ok)?

Best Regards,
sephe

--
Tomorrow Will Never Die

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Updated by ftigeot over 12 years ago

File tcpdump-sendfile.txt tcpdump-sendfile.txt added

I've reproduced the issue with a single file (the DragonFly logo).
Complete URL is http://dl.wolfpond.org/small_logo.png

Trace attached.

Now that I'm always using the same image, I've noticed the download systematically freezes in the same place, at about 90% of the height.

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Updated by ftigeot over 12 years ago

Status changed from New to Closed
% Done changed from 0 to 100

This bug is caused by the use of TCP_NOPUSH in association with sendfile(2) in the Apache-2.4 code.

Thanks for Sepherosa Ziehau for pointing it.

Bug reports will be filled with pkgsrc and the upstream project.

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Updated by sepherosa over 12 years ago

On Thu, May 17, 2012 at 5:50 PM, Francois Tigeot via Redmine
<bugtracker-admin@leaf.dragonflybsd.org> wrote:

Issue #2368 has been updated by Francois Tigeot.

Status changed from New to Closed
% Done changed from 0 to 100

This bug is caused by the use of TCP_NOPUSH in association with sendfile(2) in the Apache-2.4 code.

Please test unpatched apache-2.4 w/ the following commit.
3533a1834a0ba3a7c441ede5120c3720d8a34c4c

Best Regards,
sephe

Thanks for Sepherosa Ziehau for pointing it.

Bug reports will be filled with pkgsrc and the upstream project.
----------------------------------------
Bug #2368: sendfile(2) freezes for a few seconds
http://bugs.dragonflybsd.org/issues/2368

Author: Francois Tigeot
Status: Closed
Priority: Normal
Assignee:
Category:
Target version:

Having updated a web server to apache-2.4 (sendfile enabled), I noticed
some static images didn't load in one go:

- top parts are displayed instantly
- image downloads freeze for a few seconds
- missing bottom parts are then downloaded and displayed instantly

Switching EnableSendfile between on/off in httpd.conf enables or disables
this behavior 100% of the time

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