| Summary: | RFE - Explore whether an option for automating the affinity mask | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | John Kacur <jkacur> |
| Component: | rt-tests | Assignee: | John Kacur <jkacur> |
| Status: | CLOSED WONTFIX | QA Contact: | Jiri Kastner <jkastner> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | medium | ||
| Version: | 7.4 | CC: | bhu, kzhang |
| Target Milestone: | rc | Keywords: | FutureFeature |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2017-03-28 13:18:10 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Bug Depends On: | |||
| Bug Blocks: | 1353018 | ||
This feature item should be moved to the rewrite of cyclictest we are planning |
Currently, if you use the -t option without an argument cyclictest presumes that it should put a measurement thread on every online cpu. This is the original logic, which is to test the entire system. The alternative is to use -t<n> and -a<cpulist> to create <n> measurement threads and affine them to <cpulist>. One complaint I have about this is that no matter where you place the measurement threads, they're labeled 0-(n-1) in the output, so it makes it hard to map a test thread back to the cpu where it ran. Wondering if we can update the output to show the core to which a test thread is bound. I'm also wondering if we can add a third option to say "just use the cores in your current cpu affinity mask". That way you can rejigger the tuning parameters for a system and then just kick off cyclictest without having to figure out how your -a/-t options should change to match. I'm thinking where we've diddled the isolcpus= boot parameter and want to try cyclictest over there like this: # presumes isolcpus=0,12 taskset --cpus=0,12 cyclictest -p95 -mn --affinity-mask So that we'd get two measurment threads, affine to cpus 0 and 12. I realize that we could do this with '-t2 -a0,12' but I was hoping to simplify things.