Stage level scheduling does not allow you to change configs right now. This is
something we thought about as follow on but have never implemented. How many
tasks on the DL stage are you running? The typical case is run some etl lots
of tasks... do mapPartitions and then run your DL stuff, before that
mapPartitions you could do a repartition if necessary to get to exactly the
number of tasks you want (20). That way even if maxExecutors=500 you will only
ever need 20 or whatever you repartition to and spark isn't going to ask for
more then that.
Tom
On Thursday, November 3, 2022 at 11:10:31 AM CDT, Shay Elbaz
<[email protected]> wrote:
#yiv8086956851 P {margin-top:0;margin-bottom:0;}Thanks again Artemis, I really
appreciate it. I have watched the video but did not find an answer.
Please bear with me just one more iteration 🙂
Maybe I'll be more specific:Suppose I start the application with
maxExecutors=500, executors.cores=2, because that's the amount of resources
needed for the ETL part. But for the DL part I only need 20 GPUs. SLS API only
allows to set the resources per executor/task, so Spark would (try to) allocate
up to 500 GPUs, assuming I configure the profile with 1 GPU per executor. So,
the question is how do I limit the stage resources to 20 GPUs total?
Thanks again,Shay
From: Artemis User <[email protected]>
Sent: Thursday, November 3, 2022 5:23 PM
To: [email protected] <[email protected]>
Subject: [EXTERNAL] Re: Re: Stage level scheduling - lower the number of
executors when using GPUs
|
ATTENTION: This email originated from outside of GM.
|
Shay, You may find this video helpful (with some API code samples that you
are looking for). https://www.youtube.com/watch?v=JNQu-226wUc&t=171s. The
issue here isn't how to limit the number of executors but to request for the
right GPU-enabled executors dynamically. Those executors used in pre-GPU
stages should be returned back to resource managers with dynamic resource
allocation enabled (and with the right DRA policies). Hope this helps..
Unfortunately there isn't a lot of detailed docs for this topic since GPU
acceleration is kind of new in Spark (not straightforward like in TF). I wish
the Spark doc team could provide more details in the next release...
On 11/3/22 2:37 AM, Shay Elbaz wrote:
#yiv8086956851 #yiv8086956851 --p {margin-top:0;margin-bottom:0;}#yiv8086956851
Thanks Artemis. We are not using Rapids, but rather using GPUs through the
Stage Level Scheduling feature with ResourceProfile. In Kubernetes you have to
turn on shuffle tracking for dynamic allocation, anyhow.The question is how we
can limit thenumber of executors when building a new ResourceProfile, directly
(API) or indirectly (some advanced workaround).
Thanks,Shay
From: Artemis User<[email protected]>
Sent: Thursday, November 3, 2022 1:16 AM
To: [email protected] <[email protected]>
Subject: [EXTERNAL] Re: Stage level scheduling - lower the number of executors
when using GPUs
|
ATTENTION: This email originated from outside of GM.
|
Are you using Rapids for GPU support in Spark? Couple of options you may
want to try:
- In addition to dynamic allocation turned on, you may also need to turn on
external shuffling service.
- Sounds like you are using Kubernetes. In that case, you may also need to
turn on shuffle tracking.
- The "stages" are controlled by the APIs. The APIs for dynamic resource
request (change of stage) do exist, but only for RDDs (e.g. TaskResourceRequest
and ExecutorResourceRequest).
On 11/2/22 11:30 AM, Shay Elbaz wrote:
#yiv8086956851 #yiv8086956851 --p {margin-top:0;margin-bottom:0;}#yiv8086956851
Hi,
Our typical applications need lessexecutors for a GPU stage than for a CPU
stage. We are using dynamic allocation with stage level scheduling, and Spark
tries to maximize the number of executors also during the GPU stage, causing a
bit of resources chaos in the cluster. This forces us to use a lower value for
'maxExecutors' in the first place, at the cost of the CPU stages performance.
Or try to solve this in the Kubernets scheduler level, which is not
straightforward and doesn't feel like the right way to go.
Is there a way to effectively use less executors in Stage Level Scheduling? The
API does not seem to include such an option, but maybe there is some more
advanced workaround?
Thanks,Shay
