Here is a shortened version of the first log. Let’s see what we can learn from it:
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Log
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2020-09-14 12:59:25: 0: Loading Job's Plugin timeout is Disabled
2020-09-14 12:59:27: 0: Executing plugin command of type 'Sync Files for Job'
2020-09-14 12:59:27: 0: Plugin rendering frame(s): 1
2020-09-14 12:59:28: 0: Executing plugin command of type 'Render Task'
2020-09-14 12:59:28: 0: INFO: Process is now running
2020-09-14 12:59:30: 0: STDOUT: Redshift Command-Line Renderer (version 3.0.28 - API: 3023)
2020-09-14 12:59:31: 0: STDOUT: Initializing GPUComputing module (CUDA). Ordinal 0
2020-09-14 12:59:31: 0: STDOUT: Initializing GPUComputing module (CUDA). Ordinal 1
2020-09-14 12:59:32: 0: STDOUT: OptiX denoiser init...
2020-09-14 12:59:32: 0: STDOUT: Loading Redshift procedural extensions...
2020-09-14 12:59:32: 0: STDOUT: Loading: C:\Users\Agata\Desktop\render\RS Ref Path_v01.RS\RS Ref Path_v01.001.rs
2020-09-14 12:59:32: 0: STDOUT: License acquired
2020-09-14 12:59:32: 0: STDOUT: HID rehost=f96bfd190a59202ea8994d4b4029428f2f5ebf8b.0
2020-09-14 12:59:33: 0: STDOUT: Time to process all materials and shaders: 1.059111 seconds
2020-09-14 12:59:33: 0: STDOUT: Allocating GPU mem...(device 0)
2020-09-14 12:59:34: 0: STDOUT: Done (Allocator size: 6268 MB. CUDA reported free mem before: 8616 MB, after: 1079 MB)
2020-09-14 12:59:34: 0: STDOUT: Allocating GPU mem...(device 1)
2020-09-14 12:59:34: 0: STDOUT: Failed to leave 878 MB free (remainder: 223 MB). Trying again
2020-09-14 12:59:35: 0: STDOUT: Done (Allocator size: 7362 MB. CUDA reported free mem before: 8628 MB, after: 1044 MB)
2020-09-14 12:59:35: 0: STDOUT: Allocating GPU mem for ray tracing hierarchy processing
2020-09-14 12:59:35: 0: STDOUT: Irradiance point cloud...
2020-09-14 12:59:36: 0: STDOUT: Total irradiance point cloud construction time 1.1s
2020-09-14 12:59:36: 0: STDOUT: Rendering blocks... (resolution: 1920x1080, block size: 128, unified minmax: [16,256])
2020-09-14 13:00:01: 0: STDOUT: Processing blocks...
2020-09-14 13:00:01: 0: STDOUT: Time to render 135 blocks: 25.7s
2020-09-14 13:00:01: 0: STDOUT: Rendering time: 29.4s (2 GPU(s) used)
2020-09-14 13:00:02: 0: STDOUT: Saving: RS Ref Path_v01\RS Ref Path_v01.001.exr
2020-09-14 13:00:02: 0: STDOUT: Saving: C:\Users\Agata\Desktop\render\RS Ref Path_v01\RS Ref Path_v01.P.001.exr
2020-09-14 13:00:02: 0: STDOUT: Saving: C:\Users\Agata\Desktop\render\RS Ref Path_v01\RS Ref Path_v01.Z.001.exr
2020-09-14 13:00:02: 0: STDOUT: Saving: RS Ref Path_v01\RS Ref Path_v01.001.exr
2020-09-14 13:00:06: 0: STDOUT: License returned
2020-09-14 13:00:07: 0: STDOUT: Saving: C:\Users\Agata\Desktop\render\RS Ref Path_v01\RS Ref Path_v01.proxy.001.exr
2020-09-14 13:00:07: 0: STDOUT: Shutdown Rendering Sub-Systems...
2020-09-14 13:00:08: 0: STDOUT: Finished Shutting down Rendering Sub-Systems
2020-09-14 13:00:08: 0: INFO: Process exit code: 0
2020-09-14 13:00:08: 0: Done executing plugin command of type 'Render Task'
The task starts at timestamp 12:59:25. The actual plugin job synchronization starts 2 seconds later. The render task start at 59:28. The Redshift Executable is launched at 59:30. So it takes about 5 seconds before the Redshift Standalone is called. This is more or less Deadline Worker overhead.
The Redshift starts initializing, and at 59:32 it loads the scene. It takes another second to evaluate the shaders at 59:33. At 59:35 it starts the Irradiance Point Cloud calculations, which take 1.1s. So we have spent 10 seconds so far before the actual raytracing begins.
At 59:36 it starts the rendering of 135 blocks, which takes 25.7 seconds on 2 GPUs and finishes at 13:00:01.
From 00:02 to 00:06 is saves the output, then returns the license. There is a proxy EXR saving that takes another second before the Rendering Sub-System shutdown starts, and ends another second later at 00:08. At that same time, it finishes the task. So this is 7 seconds after the rendering of blocks reported 29.4 seconds of rendering.
This means about 10 seconds before rendering the blocks, 25.7 seconds rendering blocks, and about 7 seconds after rendering to save images, shut down and finish. This comes to 42.7 or more or less 43 seconds.
The 29.4 seconds seem to be counted from the moment the scene is loaded to the moment the blocks have been rendered. So the overhead of running Deadline and Redshift Standalone is about 13 seconds.
The problem is that the Redshift Standalone overhead still exists when you run from the command line without Deadline, but it stays unreported because there are no time stamps between where you call the command line and where the actual scene is loaded and the 29.4 seconds are counted until the end of the blocks rendering. Redshift still spends a few seconds loading the executable, allocating memory, releasing licenses, and shutting down the renderer, but that overhead is not captured in numbers. At least the Deadline log gives you explicit time stamps for every single step.
In other words, we can assume that of the 13 seconds combined overhead in the Deadline Task, about 5 seconds are due to Deadline copying data around, and about 8 seconds are loading/unloading the renderer. You can try to use a stopwatch when running the manual command line to see if this is true. I would expect the actual process from calling the command to the prompt reappearing to be around 40 seconds…
I cannot answer why the render time inside of Houdini is only 21 seconds. If you take 4m 38s and turn it into seconds, it is 4*60+38=278 seconds. Divided by 10 it would mean 27.8 seconds per frame. This is still faster than the 29.4 we got in some of the Standalone tests, so for some reason Redshift runs faster inside of Houdini… It is possible that since some libraries are pre-loaded, rendering inside it does not have any overhead. Remember that the pure rendering time (Irradiance point cloud, Rendering blocks) is actually around 26 seconds in Redshift Standalone. So it is plausible that Houdini just has everything needed in memory already, and all it does is the pure rendering process without any other overhead. Where did you get the 21s figure from?