1.    Look in PCI configuration space to find the Base Address Register (BAR) for the memory controller device.  You can do this with "setpci -s 0:0.0 0x48.l" (run as root).  This will give you a 32-bit physical address in Memory-Mapped IO space that maps to the memory controller.
  2.  Double-check the address against the mappings given by "cat /proc/iomem".
    In a program run by the root user, execute an mmap() function on /dev/mem at the offset specified above.  This will return a pointer to a virtual address that will point to that memory-mapped IO range.  I recommend assigning this pointer to an array of "uint32_t".
   3. Read the initial value of the DRAM_DATA_READS counter by accessing array element 0x5050/4 = 0x1414 = 5140 (decimal).  If you simply assign that array value to a scalar the compiler should generate a 32-bit load operation, which is the only memory access type that will give you the correct answer for 32-bit fields in Memory-Mapped IO regions.
   4.  Read the initial value DRAM_DATA_WRITES counter by accessing array element 0x5054/4=0x1415 = 5141 (decimal).
 5.   Optionally read the DRAM_GT_REQUESTS, DRAM_IA_REQUESTS, and DRAM_IO_REQUESTS using the same approach.   Read the documentation on the monitoring-integrated-memory-controller web page very carefully so that you understand what these mean.
 6.   At intervals of 10 seconds or less, read the counters again, compute the differences, correct for overflow (if applicable), and add the increments into 64-bit integers.  A background process that executes a ten-second "sleep()" call should be safe -- under realistic conditions the counters won't wrap in under 11-12 seconds, so the small amount of uncertainty in the wakeup time from the "sleep()" call is OK.
   7. Repeat step 6 until your workload is completed.    My code includes a signal handler to accept the "SIGCONT" signal from user space that I send when the workload is completed (using "kill -SIGCONT pid_of_monitoring_program") since SIGCONT is the only signal that a process owned by root will accept from a non-root user process.  (Be careful of using signal numbers, the SIGCONT signal is assigned to different numerical values in different Linux versions.)