po 3. 2. 2025 v 10:04 odesÃlatel Tomas Glozar <[email protected]> napsal: > A proof-of-concept bpftrace script using this feature: > https://gitlab.com/-/snippets/4801190 >
I added another PoC using event histograms to the snippet. That one captures data from all CPUs, and thus can be used for testing on machines with a high number of CPUs where rtla cannot keep up with timerlat samples (in our measurements, >100). There seems to be an issue with division where most values are rounded up, e.g.: max: 135 timer_latency: 134657 This also affects the main histogram and seems to be specific to the event histogram PoC. The bpftrace one shows exactly the same results as rtla when run concurrently with it. Another difference compared to the bpftrace PoC is that you have to calculate averages manually from the latency sum and the sample count. Tomas
