simulation speed when there are multi-bunches and muti-IBS element
Posted: 11 Jul 2023, 08:37
Dear Michael,
Recently, we are trying to simulate the multi-bunch together with multi-IBS scatter element. We are trying to see the computation efficiency of the for different scenarios.
The 6 cases we studied are
1. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, multi-IBS at every sextupoles.
2. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, one IBS at the end of the ring.
3. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, no IBS
4. 1 bunch, 800K particles in total, multi-IBS at every sextupoles,
5. 1 bunch, 800K particles in total, one IBS at the end of the ring.
6. 1 bunch, 800K particles in total, no IBS
The simulations are launched in the same condition (64 cpus and 10 turns in total), the time consumed are listed below:
For multi-bunch cases:
case 1: 13:00 minutes; case 2: 6:00 minutes; case 3: 6:00 minutes
For single-bunch case:
case 4: 6:34 minutes; case 5: 5:57 minutes; case 6: 6:08 minutes
Seems like that, for single bunch simulation, the IBS does not cost too much extra CPU time. The simulation time increases from 6 minutes to 6.5 minutes
Whereas for multi-bunches case, if IBS scatter element number is 1, it does not cost extra time, however, if multi-IBS scatter elements are set as case 1, the simulation time will be significantly increased.
Seems like for the multi-bunch, multi-IBS scatter element, we can not get very good speed up. I understand, in general one IBS at the end of the ring is good enough, however, it is very curious about the reason why muti-Ibs setting slows down the computation. Would you please make some comment on that?
yours Chao
Recently, we are trying to simulate the multi-bunch together with multi-IBS scatter element. We are trying to see the computation efficiency of the for different scenarios.
The 6 cases we studied are
1. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, multi-IBS at every sextupoles.
2. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, one IBS at the end of the ring.
3. 80 bunches, (load in &sdds_beam command and data is separated by page), and each bunch contain 10K particles, no IBS
4. 1 bunch, 800K particles in total, multi-IBS at every sextupoles,
5. 1 bunch, 800K particles in total, one IBS at the end of the ring.
6. 1 bunch, 800K particles in total, no IBS
The simulations are launched in the same condition (64 cpus and 10 turns in total), the time consumed are listed below:
For multi-bunch cases:
case 1: 13:00 minutes; case 2: 6:00 minutes; case 3: 6:00 minutes
For single-bunch case:
case 4: 6:34 minutes; case 5: 5:57 minutes; case 6: 6:08 minutes
Seems like that, for single bunch simulation, the IBS does not cost too much extra CPU time. The simulation time increases from 6 minutes to 6.5 minutes
Whereas for multi-bunches case, if IBS scatter element number is 1, it does not cost extra time, however, if multi-IBS scatter elements are set as case 1, the simulation time will be significantly increased.
Seems like for the multi-bunch, multi-IBS scatter element, we can not get very good speed up. I understand, in general one IBS at the end of the ring is good enough, however, it is very curious about the reason why muti-Ibs setting slows down the computation. Would you please make some comment on that?
yours Chao