That was an example. Now my concern is: Flexus3.0 has a parameter MAX_FLEXPOINTS=28 in the create-flexpoints which should be predetermined. Also in Flexus4.0, the commandrun_job -postprocess "$SCRIPT_ROOT/postprocess_ckptgen.sh flexpoint 28 test_app" -cfg trace... need to know the maximum number of flexpoints.
Consider the true value for number of flexpoints is 28 but I don't know that so I enter 50. Is it ok? Two states are possible: 1- after the 28th flexpoint, the simulation ends because flexus found that the magic break is executed. So there will be no folder from flexpoints_029 through flexpoint_050. 2- Flexus ignores the magic break and continue to create more flexpoints from flexpoints_029 through flexpoint_050. Since my code is finished at the 28th, the remaining flexpoints will contain OS background activities (I say that over-simulation) Which one is true for flexus? // Naderan *Mahmood; ________________________________ From: Volos Stavros <[email protected]> To: Mahmood Naderan <[email protected]> Cc: simflex <[email protected]> Sent: Sat, June 19, 2010 4:49:18 PM Subject: Re: Avoiding under or over simulation in warm simulation If I understood correctly you need to simulate a particular region. It seems that this region takes only 15000000 cycles. So creating 3-4 flexpoints will not give you a good confidence interval. I would recommend you to use smaller interval and run some timing simulations to see the confidence interval. I agree that you don't need to know the maximum number because your region of interest is a fixed part of your code. Regards, -Stavros On Jun 19, 2010, at 1:40 PM, Mahmood Naderan wrote: How about using magic break at the end of the ROI. For example suppose that we don't know how many instructions or cycles are going to execute. As you said, we have phase_000 which is actually the cold checkpoint. Now when we launch the create flexpoint file with 5000000 interval, the logic is: >1 ~ 5000001 => flexpoint_01 >5000002 ~ 10000002 => flexpoint_02 >10000003 ~ 15000003 => flexpoint_03 > >At this point we see this: >15000003 ~ 15006531 => magic break is execute => flexpoint_04 => quit > >Now we can see that 4 flexpoints are created and the warm simulation ends. No >need to know the maximum number. Do you agree with that? > >// Naderan *Mahmood; > > > > > ________________________________ From: Volos Stavros <[email protected]> >To: Mahmood Naderan <[email protected]> >Cc: simflex <[email protected]> >Sent: Sat, June 19, 2010 2:52:38 PM >Subject: Re: Avoiding under or over simulation in warm simulation > >Hi Mahmood, > > >I suppose that you have already created a simics checkpoint (i.e. phase_000) > > >The number of flexpoints depends on the workload that you have. When creating >flexpoints >there are two parameters: >a) How many flexpoints you create >b) How many cycles you simulate before take the flexpoint (interval) > > >For example if the interval is 5000000 cycles and the number of flexpoints are >80, you will >simulate 400000000 cycles. This can be transformed to real time so if you want >to simulate >your workload for 5s real time you should estimate how many cycles you need. > > >How many flexpoints and what the ideal interval is it depends on your >workload. > > >Personally when I created flexpoints for two different transactions of an oltp >workload, the two >transactions needed different interval/number of flexpoints. The metric that >you should use to >see if the flexpoints are reliable is that the 95% confidence interval of the >average IPC of your >workload should be less than 5%. > > >Regards, >-Stavros > > > > >On Jun 19, 2010, at 7:58 AM, Mahmood Naderan wrote: > >Hi, >>I want to create flexpoints for my own workload. Considering the region of >>interest: >>// initialize >>BEGIN_ROI // will send a magic break to create a cold checkpoint >>// core >>FINISH_ROI // will send a magic break to stop the warm simulation >>// finalize >> >> >>I want to know how many flexpoint should I create since number of flexpoints >>is given as an argument to the commandline? >> >>Logically the warm-up simulation (create flexpoint phase) should be stoped at >>either maximum number of flexpoints given to the command or the magic break >>just before FINISH_ROI. Anything else will be result in under simulation or >>over simulation. >> >>Thanks, >>// Naderan *Mahmood; >> >> > > >
