Re: [gem5-users] simObject clocks and global simulation clock

[Andreas Hansson via gem5-users]

Hi Anny,

The short answer: there is no global “clock” in gem5

The long answer: There is a global absolute time in gem5, and it is measured in 
the abstract unit “Ticks”, defaulting to 1 ps. Do not think of Ticks as clock 
cycles. Instead, it is effectively the resolution of a digitised continuous 
time scale that everyone agrees on. 10 Ticks is the same to every object, just 
like 50 ns is the same.

The clocks in the different objects are used to enable us to express time 
(throughput and latency) in cycles. For example, a module might have a delay of 
3 Cycles, and that then gets translated to a absolute time (Ticks) by 
multiplying with the current clock of the clock domain. Thus, what a cycle 
means is different for different objects, and also possibly changing over time. 
At run time we turn relative time in cycles into absolute time when 
scheduling/executing events in the system.

I hope that answers your question.

Andreas

From: Vanchinathan Venkataramani via gem5-users 
mailto:gem5-users@gem5.org>>
Reply-To: Vanchinathan Venkataramani 
mailto:dcsv...@gmail.com>>, gem5 users mailing list 
mailto:gem5-users@gem5.org>>
Date: Tuesday, December 16, 2014 at 4:04 PM
To: Anny mailto:anya.k...@gmail.com>>, gem5 users mailing 
list mailto:gem5-users@gem5.org>>
Subject: Re: [gem5-users] simObject clocks and global simulation clock

Ticks is the basic unit of time in gem5.  gem5 uses this for synchronization. 
Every system cycle is made up of n number of ticks ticks.


For a system unit with frequency = 2 GHZ, one cycle = 500 ticks

On Tue, Dec 16, 2014 at 7:04 PM, Anny via gem5-users 
mailto:gem5-users@gem5.org>> wrote:
Hi all,

I have a question about clocks on gem5. In gem5, it seems that there is a
global simulation clock and every simObject has a clock domain. The eventq
is sorted in time. When two objects with two different clocks schedule two
events on eventq, how the order is determined since the two objects have
different clocks? Are all objects synchronious? it seems that everything in
the system is based of one clock (global simulation clock)? It is binding.


Best,
Anny.

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[gem5-users] modifying the components of gem5

[babak aghaei via gem5-users]

Dear Andreas HanssonI prey this msg find you in complete health and full 
happiness state. 
I have been studying gem5 simulator for last 10 month ago. but now because 
information starvation i am stopping my research.  if possible plz guide me in 
following issues:1. when i want to modify a file in gem5 component, how i can 
see the result in stats.txt? my mean is what i must be do after modifying this 
file until see the result.2. my main studies are on faults and fault injection 
to network on chip. in continue my studies, i want know about router idle time. 
I want know weather the router have idle time on not, if yes where i can 
realize that.3. I want to modify the router files(which file must be change 
from .cc .h .py)? 
4. if i wanna modify the flit structure what i must be do?sry if my questions 
are heterogeneous. i am really confused.i wait for kindly response..Best
 ---Babak Aghaei 
Ph.D candidate
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Re: [gem5-users] simObject clocks and global simulation clock

[Vanchinathan Venkataramani via gem5-users]

Ticks is the basic unit of time in gem5.  gem5 uses this for
synchronization. Every system cycle is made up of n number of ticks ticks.


For a system unit with frequency = 2 GHZ, one cycle = 500 ticks

On Tue, Dec 16, 2014 at 7:04 PM, Anny via gem5-users 
wrote:
>
> Hi all,
>
> I have a question about clocks on gem5. In gem5, it seems that there is a
> global simulation clock and every simObject has a clock domain. The eventq
> is sorted in time. When two objects with two different clocks schedule two
> events on eventq, how the order is determined since the two objects have
> different clocks? Are all objects synchronious? it seems that everything in
> the system is based of one clock (global simulation clock)? It is binding.
>
>
> Best,
> Anny.
>
> ___
> gem5-users mailing list
> gem5-users@gem5.org
> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
>
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[gem5-users] simObject clocks and global simulation clock

[Anny via gem5-users]

Hi all,

I have a question about clocks on gem5. In gem5, it seems that there is a
global simulation clock and every simObject has a clock domain. The eventq
is sorted in time. When two objects with two different clocks schedule two
events on eventq, how the order is determined since the two objects have
different clocks? Are all objects synchronious? it seems that everything in
the system is based of one clock (global simulation clock)? It is binding.


Best, 
Anny.

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