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Bug 1632854
Summary: | lscpu miss reports CPUs in a mixed cluster | ||||||
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Product: | [Fedora] Fedora | Reporter: | Peter Robinson <pbrobinson> | ||||
Component: | util-linux | Assignee: | Karel Zak <kzak> | ||||
Status: | CLOSED UPSTREAM | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||
Severity: | unspecified | Docs Contact: | |||||
Priority: | unspecified | ||||||
Version: | rawhide | CC: | jonathan, kzak | ||||
Target Milestone: | --- | Keywords: | Tracking | ||||
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: | 2020-07-07 09:46:15 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: | |||||||
Bug Depends On: | |||||||
Bug Blocks: | 245418 | ||||||
Attachments: |
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Description
Peter Robinson
2018-09-25 17:21:19 UTC
This message is a reminder that Fedora 29 is nearing its end of life. Fedora will stop maintaining and issuing updates for Fedora 29 on 2019-11-26. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '29'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 29 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. Still an issue This scenario is unsupported by lscpu. It assumes the same CPUs in all sockets and all topology is estimated from CPU0. It will require huge changes to fix it :-( Anyway, added to the upstream TODO file. We'll see. Thanks for your report. It would be nice to have a dump from your unique /sys and /proc for testing purposes. Please, send me output (tarball) from https://raw.githubusercontent.com/karelzak/util-linux/master/tests/ts/lscpu/mk-input.sh. Thanks! Created attachment 1659239 [details]
Output of mk-input.sh
(In reply to Karel Zak from comment #3) > This scenario is unsupported by lscpu. It assumes the same CPUs in all > sockets and all topology is > estimated from CPU0. It will require huge changes to fix it :-( Yes, sadly asymetric processors are a thing, in the early cases of arm's big.LITTLE they were clusters of processor types, initially 2 now up to 4 (I think). With their next gen of this, called DynamIQ, each processor core could be different and they're all independent. Intel is also introducing a similar technology on some of their devices so sadly it's not some weird short lived thing. > It would be nice to have a dump from your unique /sys and /proc for testing > purposes. > > Please, send me output (tarball) from Attached. I'm working on a new lscpu code (https://github.com/karelzak/util-linux/tree/topic/lscpu), but it's not ready yet. I'll close this issue here as we need to resolve it in upstream tree first. Small update, debug message from new lscpu on your /sys and /proc 428128: lscpu: TYPE: [0x611000000040]: reading 0x41/0xd03/ topology 428128: lscpu: TYPE: [0x611000000040]: nthreads: 4 428128: lscpu: TYPE: [0x611000000040]: ncores: 4 428128: lscpu: TYPE: [0x611000000040]: nsockets: 1 428128: lscpu: TYPE: [0x611000000040]: nbooks: 0 428128: lscpu: TYPE: [0x611000000040]: ndrawers: 0 428128: lscpu: TYPE: [0x611000000540]: reading 0x41/0xd08/ topology 428128: lscpu: TYPE: [0x611000000540]: nthreads: 2 428128: lscpu: TYPE: [0x611000000540]: ncores: 2 428128: lscpu: TYPE: [0x611000000540]: nsockets: 1 428128: lscpu: TYPE: [0x611000000540]: nbooks: 0 428128: lscpu: TYPE: [0x611000000540]: ndrawers: 0 I guess the numbers are correct for each of the types. (In reply to Karel Zak from comment #7) > Small update, debug message from new lscpu on your /sys and /proc > > 428128: lscpu: TYPE: [0x611000000040]: reading 0x41/0xd03/ topology > 428128: lscpu: TYPE: [0x611000000040]: nthreads: 4 > 428128: lscpu: TYPE: [0x611000000040]: ncores: 4 > 428128: lscpu: TYPE: [0x611000000040]: nsockets: 1 > 428128: lscpu: TYPE: [0x611000000040]: nbooks: 0 > 428128: lscpu: TYPE: [0x611000000040]: ndrawers: 0 > 428128: lscpu: TYPE: [0x611000000540]: reading 0x41/0xd08/ topology > 428128: lscpu: TYPE: [0x611000000540]: nthreads: 2 > 428128: lscpu: TYPE: [0x611000000540]: ncores: 2 > 428128: lscpu: TYPE: [0x611000000540]: nsockets: 1 > 428128: lscpu: TYPE: [0x611000000540]: nbooks: 0 > 428128: lscpu: TYPE: [0x611000000540]: ndrawers: 0 > > I guess the numbers are correct for each of the types. The number of cores are, what does the name map through to for the lookup? Should be Cortex-A72 for the second pair and Cortex-53 for the quad group. Not sure of the stepping/revision. The implementer and type are translated later in the code, it's: 0x41, "ARM" 0xd03, "Cortex-A53" (4 cores) 0xd08, "Cortex-A72" (2 cores) The question is how to display mixed CPUs on lscpu output, maybe for humans CPU(s): 6 ├─ Cortex-A53 │ Thread(s) per core: 1 │ Core(s) per socket: 4 │ Socket(s): 1 └─ Cortex-A72 Thread(s) per core: 1 Core(s) per socket: 2 Socket(s): 1 > 0xd03, "Cortex-A53" (4 cores) > 0xd08, "Cortex-A72" (2 cores) That's correct. > The question is how to display mixed CPUs on lscpu output, maybe for humans That's a very good question. So for this generation of HW I think the below is about correct. The term that is used is "clusters" and most will have two clusters, in some of the newer high end devices there's actually 3 clusters, often in 2/2/4 or 2/4/4 combinations. > CPU(s): 6 > ├─ Cortex-A53 > │ Thread(s) per core: 1 > │ Core(s) per socket: 4 > │ Socket(s): 1 > └─ Cortex-A72 > Thread(s) per core: 1 > Core(s) per socket: 2 > Socket(s): 1 In the newer generations there's a technology that Arm calls DynamIQ [1] which means the cores are basically all independent and they can power any or nearly all cores off and they can come and go. Intel is doing something similar with their latest gen too. I'm not sure what would be the best way to display those and I don't currently have access to a DynamIQ system to even poke and see. [1] https://www.arm.com/why-arm/technologies/dynamiq It's interesting that /sys in your dump does not provide any information about caches, for "standard" CPUs there is /sys/devices/system/cpu/cpu0/cache/ directory with info about caches. |