Bug 1913750
| Summary: | glibc: memcpy calls are slower for AMD processors on RHEL 8 than RHEL 7 [rhel-8.3.0.z] | ||
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| Product: | Red Hat Enterprise Linux 8 | Reporter: | RHEL Program Management Team <pgm-rhel-tools> |
| Component: | glibc | Assignee: | Florian Weimer <fweimer> |
| Status: | CLOSED ERRATA | QA Contact: | qe-baseos-tools-bugs |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 8.2 | CC: | alanm, amike, ashankar, brclark, casantos, codonell, dj, fweimer, jaeshin, jwright, kdudka, mbliss, mcermak, mkolbas, mnewsome, pfrankli, sajan.karumanchi, sipoyare, skolosov, tnagata, vmukhame, yama, yoguma |
| Target Milestone: | rc | Keywords: | Bugfix, Patch, Triaged, ZStream |
| Target Release: | 8.0 | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | glibc-2.28-127.el8_3.2 | Doc Type: | Bug Fix |
| Doc Text: |
Cause: On x86-64, the glibc implementation of string functions wrongly estimated the amount of last-level cache available to a thread.
Consequence: Calling memcpy on large buffers could negatively impact overall cache performance of the system, or the memcpy call itself could be slow.
Fix: The last-level cache size is no longer scaled with the number of reported hardware threads in the system.
Result: The string functions bypass caches for large buffers (and only for large buffer), avoiding undue cache impact on the rest of the system.
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Story Points: | --- |
| Clone Of: | 1880670 | Environment: | |
| Last Closed: | 2021-02-16 14:36:33 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: | 1880670 | ||
| Bug Blocks: | 1913656 | ||
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Comment 5
Florian Weimer
2021-01-13 12:49:29 UTC
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (glibc bug fix and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2021:0556 |