Replies: 2 comments 6 replies
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Hello @dvhh, You need to use a framework or language feature for this. For example, on node this is done by libuv (I think), in C with |
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Hello @jcupitt, Mainly targeting C, would like to write a module for nginx that is using libvips, was able to put up some prototype and am of course looking at the wrong places for potential optimizations :). In a more serious fashion, I would like the module to yield to the event loop once the operation has been started, and leave it to the event loop to check for operation completion. maybe I have been looking at the wrong place for the nodejs async code, I will look deeper into the problem, although some pointers might certainly help a lot. |
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thanks, that a good start and can dig from there Basically if I understand correctly: |
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Look like nginx also have its own threadpool, will compare both. Thanks again for pushing me in the right direction |
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Don't set a flag for completion, you'll hit all kinds of thread sync races and performance issues from polling. You can't safely set a flag in one thread and see the result in another, unless you explicitly code a memory barrier. Instead, queue an event on the nginx main loop and include all of the results of the background computation (eg. a reference to the image that has been computed). |
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Also, back in the day I could clock bubble bobble on one coin, so I appreciate your avatar. |
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Thanks @jcupitt was able to do it For the curious, nginx also have threadpool, with user defined completion handler passed via a structure used to define the task. Memory pool lifetime caused me some initial issue, but nginx object allow for some request buffering indicator flag which helped extend the lifetime beyond the normal code flow. |
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Hello,
As far as I understand, libvips operations are running on a thread pool, and while operation are fast, it might leave the calling thread pending.
Is there a way to call operation asynchronously and check completion status via a flag (preferable) or callback.
I have read the "asynchronous" implementation for the php and nodejs library and don't think they are suitable for my need. And I don't think my documentation combing skill might be good enough for finding what I want.
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