Thanks, Andreas. This makes sense.
Post by Andreas Hansson
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 âlow water markâ.
Date: Wednesday, 15 April 2015 19:13
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.
Any help is appreciated.
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