libvips - glib resource temporarily available

[jarodium]

Hello,

I am getting some errors probably related to creating threads em some kind of resource temporarily unavailable.

Assume somefile.jpg has >= 3.5Mb filesize and $mime can have jpeg / webp values.

Here is the code i'm using with PHP 7.3 in a CentOS machine powered by Cpanel / Cloudlinux and with libvips 8.5.6 :

`
header("Content-type: image/$mime");

$image = Vips\Image::thumbnail("somefile.jpg",320);

$buffer = $image->writeToBuffer($ext);

echo $buffer;
`

I am having the following error messages from PHP:

`
[28-Oct-2019 09:46:31 Europe/Lisbon] PHP Fatal error: Uncaught Jcupitt\Vips\Exception: glib: Error creating thread: Resource temporarily unavailable

in vips/vendor/jcupitt/vips/src/Image.php:778

Stack trace:
#0 vips/vendor/jcupitt/vips/src/Image.php(1183): Jcupitt\Vips\Image::errorVips()
#1 vips/downloads/sizer.php(29): Jcupitt\Vips\Image->writeToBuffer('.jpg')
#2 {main}
thrown in vips/vendor/jcupitt/vips/src/Image.php on line 778
[28-Oct-2019 09:46:52 Europe/Lisbon] PHP Fatal error: Uncaught Jcupitt\Vips\Exception: glib: Error creating thread: Resource temporarily unavailable in vips/vendor/jcupitt/vips/src/Image.php:778

Stack trace:
#0 vips/vendor/jcupitt/vips/src/Image.php(1183): Jcupitt\Vips\Image::errorVips()
#1 vips/downloads/sizer.php(29): Jcupitt\Vips\Image->writeToBuffer('.jpg')
#2 {main}
thrown in vips/vendor/jcupitt/vips/src/Image.php on line 778

`
Is this something I need to check with my hosting provider?

[jcupitt]

Sorry, I don't know.

Perhaps your provider has set a very low thread limit? It would depend how they have set up your linux environment, but for example:

https://unix.stackexchange.com/questions/253903/creating-threads-fails-with-resource-temporarily-unavailable-with-4-3-kernel

I think you will need to ask them.

As a workaround, you can try reducing the size of the libvips threadpool. Put this in your startup code:

Vips\Config::concurrencySet(1);

Now libvips will only use one thread to calculate images.

[jarodium]

Hello @jcupitt

I will ask my provider for that issue.
How many threads is libvips configured to use by default ( is this something that has a limit in the vips code? ) ? Or does it try to use all resources available?

[jcupitt]

By default it tries to keep all available hardware threads busy, so usually 8 threads on a four core server, for example.

[jarodium]

Thank you for the help.

I will close this issue for now and give feedback as soon I have more test results.

[revathi-murali]

@jarodium Any update? I am facing the similar issue right now and any pointers would be of great help

cc @jcupitt

[jarodium]

@revathi-murali at this time I have followed @jcupitt 's recommendation and set the Concurrency to 2.

Since I'm working in a cageFs environment with more users I can't expend that much resources or allow vips to use as it pleases. It is matter or testing values. For me, setting concurrency up to 2 works. If your software still causes the error try setting to 1 or try to lazy load or queue the images somehow for processing. If it still doesnt work, you have to acquire more resources or dedicate a machine/vps for that kind of processing.

[revathi-murali]

Thanks for your suggestion. The problem is, the issue is right now happening in PROD env and I am unable to reproduce this issue in my local or stage env. Hence having a tough time to fix it as well.

@jcupitt Any idea on when thread-reuse will go live. Do you think waiting for this #1492 to get released will be helpful?