Reading simulation time to a variable

Hi Pedro.

The "time" command lets you report the current time, as well as doing math operations on time values. Refer to the Xcelium Tcl docs.

xcelium> time

0 FS

xcelium> time ns

0 NS

xcelium> set now [time ns]

0 NS

xcelium> puts $now

0 NS

xcelium> 

Is there a way to read the time value while the script is running using interruptions?

Imagine that I want to use the command time and clock every 10seconds. Is that possible?

Pedro

There's no built-in way to set a real-time breakpoint, but it could be done by writing some C code to set an OS timer interrupt and some VPI code to get the timestamp and print it.

Alternatively just set a breakpoint that stops the simulation every N time units of simulated time and use the Tcl "clock" command to print the current time, would that help?

stop -create -time -relative 10ns -continue -execute { set now [time ns]; clock format [clock seconds] -format "TICK: $now == %T"; }

Thanks for your reply.
I tried the command above the following way:

1 - entered the "stop" command

2 - entered "after 5000"

I was expecting to have interruptions during the execution of the command "after 5000", but that doesn't happen.

Pedro

The "stop" command doesn't accept a "after" argument so I don't understand what you did here (nor what you mean by "after 5000").

The time-related brakpoint options are: 

-time time_spec  [-absolute]  [-relative]  [-start time_spec ]  [-modulo time_spec]

please check the docs that I linked to in my first reply, everything you need is in there.

The "time" that the stop command will generate is the CPU time. I would like to stop every 10 seconds (human time).

As I mentioned before, there is no built-in way to stop based on real time, only simulated time can be specified with the stop command. What are you actually trying to achieve? If you can explain that, maybe I can propose a way to do it based on what is supported int eh simulator...

I am trying to measure the time a simulation takes to run, but without taking into account the time the simulator is doing nothing.

So if I run a piece of code that takes 10 minutes and go for lunch for an hour and then run another piece of code that takes 10 minutes more, I would like the reported duration of the sim to be 20 minutes and not 1h:20m.

I am trying to measure the time a simulation takes to run, but without taking into account the time the simulator is doing nothing.

So if I run a piece of code that takes 10 minutes and go for lunch for an hour and then run another piece of code that takes 10 minutes more, I would like the reported duration of the sim to be 20 minutes and not 1h:20m.

OK, thanks for clarifying your request. If you just need this time measurement as a summary for the entire simulation, why not just add "-status -status3" to the xrun command line? This will result in a couple of lines at the end of the simulation log, including the actual CPU time spent:

xmsim: CPU Usage - 26.2s system + 31.0s user = 57.2s total (86.4s, 66.2% cpu) (myhost)
xrun: Time - 87.0s

Here you can see that the simulation used 87.0s of CPU time - this is not the wall-clock time but the time used actually doing work.

Thank you very much. I will try this.

Pedro

Hi Stephen,
But how do I tell xrun where to stop and measure the time?

Please note that I am entering my commands in the console.

Cheers,

Pedro

Hi Stephen

I cannot make this work.

So, do I have to call xrun as "xrun -status -status3" or as "xrun -status -status 3" ?
Am I missing something?

Best regards,

Pedro

Hi Pedro.

It's the first one: "xrun -status -status3".

The "-status" tells it to dump a CPU/memory summary at exit, and "-status3" tells it to dump the more verbose version of the summary, with a break-down for the individual tool components.

Hi,

Thanks for the answer.

But how does the simulator know when to dump the summary ? I should have to write some command to tell the simulator that I want to generate the report at that point of the code.

Otherwise, how xrun would know that the program had ended?

Hi Stephen,

Can you please give me your inputs on my last question? I would really appreciate it.

Best regards,

Pedro

The summary is dumped when you exit the simulator.

This is the output I have 

Aggregate audit (2:30:10 PM, Fri Dec 10, 2021):
Time used: CPU = 47.9 ks (13h 18m 36s), elapsed = 13 ks (3h 36m 17s), util. = 369%.
Time spent in licensing: elapsed = 20.6 s.
Peak memory used = 2.33 Gbytes.
Simulation started at: 10:53:53 AM, Fri Dec 10, 2021, ended at: 2:30:10 PM, Fri Dec 10, 2021, with elapsed time (wall clock): 13 ks (3h 36m 17s).
spectre completes with 0 errors, 89 warnings, and 22 notices.
xmsim: Memory Usage - Final: 1289.0M, Peak: 1345.3M, Peak virtual: 1734.9M
xmsim: CPU Usage - 3314.5s system + 46984.3s user = 50298.8s total (14821.7s, 100.0% cpu) (myhost)
xrun: Time - 15071.8s
TOOL: xrun(64) 20.05-t004-20201018: Exiting on Dec 10, 2021 at 14:43:02 CET (total: 04:11:12)

Do I have to divide the time, returned by the simulator, by the number of cpus I've used? Otherwise, the result doesn't make sense.

15071 seconds is 4.18h, which is more than the "wall clock" value.