Command to measure TLB misses on LINUX

Question

Could some one direct me to a command to measure TLB misses on LINUX, please? Is it okay to consider minor page faults as TLB misses?

Answer 1

You can use perf to do this. Provided your CPU supports it.

Use perf list to get some idea of the counters available. When I took this list and grepped for TLB (on my Sandy Bridge machine) I got:

rob@tartarus:~$ perf list | grep -i tlb
  dTLB-loads                                         [Hardware cache event]
  dTLB-load-misses                                   [Hardware cache event]
  dTLB-stores                                        [Hardware cache event]
  dTLB-store-misses                                  [Hardware cache event]
  dTLB-prefetches                                    [Hardware cache event]
  dTLB-prefetch-misses                               [Hardware cache event]
  iTLB-loads                                         [Hardware cache event]
  iTLB-load-misses                                   [Hardware cache event]

You can then use this particular counter with: perf record -e <event0>,<event1>,..

And then just use perf report to look at the results.

Answer 2

To see this information for the entire system, you could use the following line. This will record the counters for 1 minute (60 seconds).

perf stat -e dTLB-loads,dTLB-load-misses,iTLB-loads,iTLB-load-misses sleep 60

If miss ratio is higher than 1% you should look into using huge pages.