Bug 1265744
| Summary: | multiple guests run cyclictest tools cause guest CPU stall | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | FuXiangChun <xfu> |
| Component: | kernel-rt | Assignee: | Clark Williams <williams> |
| Status: | CLOSED NOTABUG | QA Contact: | Jiri Kastner <jkastner> |
| Severity: | high | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 7.2 | CC: | bhu, chayang, juzhang, lcapitulino, michen, qzhang |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2015-09-24 16:33:49 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: | |
| Embargoed: | |||
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Comment 4
Luiz Capitulino
2015-09-23 19:42:28 UTC
(In reply to Luiz Capitulino from comment #4) > If you're starting two guests with real-time vCPUs pinned to the same cores > in the host, that will deadlock. > > Generally speaking, each host core isolated for real-time should run only > one real-time vCPU. I see what you mean. I tested this scenario. Both guests work. In addition. 1. Customer also possible to start multiple guests with real-time vCPUs pinned to the same cores in the host. Do we have a relevant way to prevent customer? or let they know the right way. 2. Can I use cores do real-time test are not isolated in host? e.g cores 1 3 5 7(belong to node1) are isolated in host. vCPUs pinned to these cores. guest1 use them to do real-time test. cores 0 2 4 6(belong to node0) are not isolated in host. vCPUs pinned to these cores. guest2 use them do do real-time test inside guest. (In reply to FuXiangChun from comment #5) > In addition. > 1. Customer also possible to start multiple guests with real-time vCPUs > pinned to the same cores in the host. Do we have a relevant way to prevent > customer? or let they know the right way. No, there's no way to prevent this in the real-time kernel. We can write documentation warning about this, but there's no way to prevent it. > 2. Can I use cores do real-time test are not isolated in host? You may have higher latency due to other tasks re-activating the tick and/or pushing work to workqueues. I'm closing this as NOTABUG just to avoid BZs that are not real issues hanging around. |