Hi Patrick,

When it comes to the stores you are looking at a rather small number of 
operations, and my guess is that they are still in the DRAM write queues. These 
queues are not drained at the moment once the writes fall below the “low water 
mark”.

Andreas

From: Patrick <[email protected]<mailto:[email protected]>>
Reply-To: gem5 users mailing list 
<[email protected]<mailto:[email protected]>>
Date: Wednesday, 15 April 2015 19:13
To: gem5 users mailing list <[email protected]<mailto:[email protected]>>
Subject: [gem5-users] bytesWritten < (8 * number of 64-bit stores to unique 
addresses)

I am looking at stats.txt for the amount of data written to the DRAM during the 
execution of a process in full system mode. I looked at the execution trace, 
and there are at least 512 64-bit stores to unique addresses. However, 
stats.txt reports only 2,304 "bytesWritten" to the memory. It is a 4-channel 
memory configuration. "stats.txt" reports 1,152 "bytesWritten" on channel 0, 0 
"bytesWritten" to channel 1, 0 "bytesWritten" to channel 2, and 1,152 
"bytesWritten" to channel 3.

Does anyone know what would cause this? I thought maybe the data might be 
getting left in the caches, but I am waiting until the process exits before 
calling m5 resetstats. The "bytesReadDRAM" is less than expected, also, based 
on the number of loads in the instruction trace. I thought perhaps this was 
because no-write allocate was being used, but the discussion linked below 
suggests that default is to use write-allocate. I can't find where this is 
configured in gem5, so I'm not able to check this at the moment.

http://comments.gmane.org/gmane.comp.emulators.m5.users/12597

Any help is appreciated.

​-​
Patrick

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