CODEWITHSUNDEEP
clinuxmemcachedperf
shreyas42
shreyas42

Reputation: 63

Monitoring performance counters during execution of a specific function

For some context, I'm profiling the execution of Memcached, and I would like to monitor dTLB misses during the execution of a specific function. Assuming that Memcached spawns multiple threads, each thread could potentially be executing the function in parallel. One particular solution I discovered, Perf features toggle events (Using perf probe to monitor performance stats during a particular function), should let me achieve this by setting probes on function entry and exit and toggling the event counter on/off on each probe respectively.

My question is:

(a) From my understanding, perf toggle events was included as part of a branch to Linux kernel 3.x. Has this been incorporated in recent LTS releases of Linux kernel 4.x? If not, are there any other alternatives?

(b) Another workaround I found is described here: performance monitoring for subset of process execution. However I'm not too sure if this will work correctly for the problem at hand. I'm concerned since Memcached is multi-threaded, having each thread spawn a new child process may cause too much overhead.

Any suggestions?

Upvotes: 6

Views: 657

Answers (1)

Hadi Brais
Hadi Brais

Reputation: 23639

I could only find the implementation of the toggle events feature in the /perf/core_toggle repo, which is maintained by the developer of the feature. You can probably compile that code and play with the feature yourself. You can find examples on how to use it here. However, I don't think it has been accepted yet in the main Linux repo for any version of the kernel.

If you want to measure the number of one or more events, then there are alternatives that are easy to use, but require adding a few lines of code to your codebase. You can programmatically use the perf interface or other third-party tools that offer such APIs such as PAPI and LIKWID.

Upvotes: 2

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