Bug 458441
| Summary: | Make oprofile recognize Nehalem | ||||||||
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| Product: | Red Hat Enterprise Linux 5 | Reporter: | Markus Armbruster <armbru> | ||||||
| Component: | kernel | Assignee: | Markus Armbruster <armbru> | ||||||
| Status: | CLOSED ERRATA | QA Contact: | Martin Jenner <mjenner> | ||||||
| Severity: | medium | Docs Contact: | |||||||
| Priority: | medium | ||||||||
| Version: | 5.3 | CC: | andriusb, jane.lv, jvillalo, kernel-mgr, riek, rlerch, suresh.b.siddha, venkatesh.pallipadi, xen-maint, xiaowei.yang, youquan.song | ||||||
| Target Milestone: | rc | Keywords: | FutureFeature | ||||||
| Target Release: | --- | ||||||||
| Hardware: | All | ||||||||
| OS: | Linux | ||||||||
| Whiteboard: | |||||||||
| Fixed In Version: | Doc Type: | Enhancement | |||||||
| Doc Text: |
<filename>oprofile</filename> did not correctly identify processors based on the Next-Generation Intel(R) Microarchitecture (codenamed "Nehalem".) Consequently, the performance monitoring unit could not be used and the processor fell back to the timer interrupt. The kernel has been updated to resolve this issue.
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Story Points: | --- | ||||||
| Clone Of: | |||||||||
| : | 550183 (view as bug list) | Environment: | |||||||
| Last Closed: | 2009-01-20 20:07:21 UTC | Type: | --- | ||||||
| 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: | 428015, 454962, 461133, 461134 | ||||||||
| Attachments: |
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Created attachment 313820 [details]
Proposed patch for bare metal oprofile
Created attachment 313821 [details]
Proposed patch for Xenoprof
The patch for Xenoprof got accepted into xen-unstable.hg as cset 18304:3d5515f40b9b. in kernel-2.6.18-109.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5 This bug (feature request) has been marked for inclusion in the Red Hat Enterprise Linux 5.3 Release Notes. To aid in the development of relevant and accurate release notes, please fill out the "Release Notes" field above with the following 4 pieces of information: Cause: What actions or circumstances induced the feature request. Consequence: What action was inhibited by the feature's absence. Fix: What was done to implement the feature. Result: now happens when the actions or circumstances above occur. (NB: this is not the same as 'the feature request was fulfilled') Release note added. If any revisions are required, please set the "requires_release_notes" flag to "?" and edit the "Release Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Cause: oprofile didn't recognize the new Nehalem CPUs. Consequence: it could not use its performance monitoring unit, and fell back to the timer interrupt. Severe loss of functionality. Fix: backport fix from upstream. Result: oprofile fully functional. I verify on Tylersburg EP, the bug was fixed on RHEL5.3 Beta. Release note updated. If any revisions are required, please set the "requires_release_notes" flag to "?" and edit the "Release Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. Diffed Contents: @@ -1,8 +1 @@ -Cause: oprofile didn't recognize the new Nehalem CPUs. +<filename>oprofile</filename> did not correctly identify processors based on the Next-Generation Intel(R) Microarchitecture (codenamed "Nehalem".) Consequently, the performance monitoring unit could not be used and the processor fell back to the timer interrupt. The kernel has been updated to resolve this issue.- -Consequence: it could not use its performance monitoring unit, and -fell back to the timer interrupt. Severe loss of functionality. - -Fix: backport fix from upstream. - -Result: oprofile fully functional. An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2009-0225.html |
Description of problem: Oprofile needs to recognize the CPU model to make use of its PMU; it can only use timer interrupt otherwise. It doesn't recognize Nehalem, yet. Additional info: Fixed in Linus's tree: commit 4b9f12a3779c548b68bc9af7d94030868ad3aa1b Author: Linus Torvalds <torvalds> Date: Thu Jul 24 17:29:00 2008 -0700 x86/oprofile/nmi_int: add Nehalem to list of ppro cores ..otherwise oprofile will fall back on that poor timer interrupt. Also replace the unreadable chain of if-statements with a "switch()" statement instead. It generates better code, and is a lot clearer. Signed-off-by: Linus Torvalds <torvalds> Needs to be fixed separately in the Xen Hypervisor for Xenoprof.