I am trying to understand the memory output from PCM of my database server in terms of how much utliization there is.
The database server is a dual socket X5680 machine. I'm using all 3 channels of memory clocked at 800 MHz.
If I take all 3 channels of memory, would there be at best about (192 * 800 000 000) / 8 = 19 200 000 000 , or ~ 19 GByte/s of throughput? I am wondering if this is too naive (as I am guessing). Is this a bidirectional (full duplex) or is this total for both directions? Does READ / WRITE from PCM reflect this or do those numbers reflect throughput including other things than just RAM (QPI maybe?).
In a sample from my DB Server, I see it exceeds 19GByte/s, so I have a feeling there is a lot more to interpreting these columns than I am currently aware:
> summary(cpu$READ + cpu$WRITE) Min. 1st Qu. Median Mean 3rd Qu. Max. 0.616 1.717 2.750 4.555 6.140 24.030