Hi Dan,
Thank you for your response. By "start of the simulation," I’m referring to the point where the timestep is already running. As for the profiler, I can use the built-in tools in Microsoft Visual Studio 2022 on my laptop. However, the issue mainly arises towards the end of the simulation, and the last time I ran it on the workstation, it took about 4 days to complete. I could try running it for a few hours to see if the problem starts to manifest earlier. One other thought I had is that the slowdown could be related to saving around 20 functions for post-processing and plotting with GNU plot at the end. Do you think that this could be a contributing factor? The reason I’m using MCORE instead of DEM-E is because there’s already someone else in the project working on creating a particle bed using DEM-E. Instead, my thesis focus is on the vehicle itself, and since we also need to build a prototype, I’m using the previous terrain model (built with MCORE) to generate initial results while waiting for the DEM-E model to be ready. Thank you again. Gianni Il giorno martedì 24 settembre 2024 alle 18:47:05 UTC+2 Dan Negrut ha scritto: > Gianni – it might be that the initial process is associated with setting > up the simulation. > > When you say “start of the simulation”, do you mean the simulation time is > advancing, or are you referring to the “set up” stage, when there is no > time integration yet. It might be that memory operations are so > overwhelming that the CPU is stalled most of the time waiting for data to > move back and forth between CPU and RAM. This is a guess, and if you have > 30 mins and get to the bottom of it, it’d be interesting to run a profiler > on the code, to see where the time is spent during the dynamics simulation. > > > > One more question: is there a good reason you want to use MCORE? In case > you need friction and contact on a large scale, you might take a look at > Chrono DEM Engine. > > > > Dan > > --------------------------------------------- > > Bernard A. and Frances M. Weideman Professor > > NVIDIA CUDA Fellow > > Department of Mechanical Engineering > > Department of Computer Science > > University of Wisconsin - Madison > > 4150ME, 1513 University Avenue > > Madison, WI 53706-1572 > > 608 772 0914 <(608)%20772-0914> > > http://sbel.wisc.edu/ > > http://projectchrono.org/ > > --------------------------------------------- > > > > *From:* projec...@googlegroups.com <projec...@googlegroups.com> *On > Behalf Of *Gianni Curti > *Sent:* Tuesday, September 24, 2024 5:33 AM > *To:* ProjectChrono <projec...@googlegroups.com> > *Subject:* [chrono] Percentage of CPU decrease over time > > > > Hi everyone, > > I’m encountering some issues with Chrono::Multicore in my simulation, > which is based on the demo_MCORE_Cratering example. The goal is to simulate > the interaction of an object with a particle bed at rest. The code compiles > and runs without errors, but I’ve noticed an unexpected drop in CPU > utilization. > > At the start of the simulation, all the threads I allocate are working at > 80-90% capacity. However, as the simulation progresses, their utilization > gradually drops to around 10% or even lower. I had expected the > computational load to increase as the number of contacts grows from about > 7,000 to 50,000, but this CPU behavior is quite strange. > > I’ve observed this issue on both my Windows laptop (with 20 threads) and a > university workstation running Linux (with 40 threads). Has anyone else > experienced this? Could it be that the nature of the problem makes > parallelization progressively more difficult as the simulation advances? > > Thanks in advance for your help! > > Best regards, > Gianni > > -- > You received this message because you are subscribed to the Google Groups > "ProjectChrono" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to projectchron...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/projectchrono/207ae42c-461f-4ce6-b019-cd8a9d8448cfn%40googlegroups.com > > <https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/207ae42c-461f-4ce6-b019-cd8a9d8448cfn*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!Mn-N_BVwsaeaLOaZsF4s97HOvYjh5IqcOxw7-HDp_xbX7s1PAZ9DDHCyZNSdKhWwJR80RB6Jqjch6ml6kSFF$> > . > -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to projectchrono+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/adaf3ecc-3073-4e18-8696-a3e175d529ffn%40googlegroups.com.