RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 2213907 - glibc: Memcpy throughput lower on RH9.3 compared to RHEL 8.3/RHEL 7.5 - same Skylake hardware
Summary: glibc: Memcpy throughput lower on RH9.3 compared to RHEL 8.3/RHEL 7.5 - same ...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: glibc
Version: 9.3
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: rc
: ---
Assignee: DJ Delorie
QA Contact: Sergey Kolosov
Jacob Taylor Valdez
URL:
Whiteboard:
Depends On: 2180462
Blocks: 2166710
TreeView+ depends on / blocked
 
Reported: 2023-06-09 20:42 UTC by Carlos O'Donell
Modified: 2023-11-07 10:11 UTC (History)
13 users (show)

Fixed In Version: glibc-2.34-82.el9
Doc Type: Enhancement
Doc Text:
.Improved string and memory routine performance on Intel® Xeon® v5-based hardware in `glibc` Previously, the default amount of cache used by `glibc` for string and memory routines resulted in lower than expected performance on Intel® Xeon® v5-based systems. With this update, the amount of cache to use has been tuned to improve performance.
Clone Of: 2180462
Environment:
Last Closed: 2023-11-07 08:37:51 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-159421 0 None None None 2023-06-09 20:43:18 UTC
Red Hat Product Errata RHBA-2023:6582 0 None None None 2023-11-07 08:38:14 UTC

Comment 1 Carlos O'Donell 2023-06-09 20:43:13 UTC 
In RHEL 9 we should review the amount of L3 used for in-flight memory copies and adjust based on upstream discussions with Intel.

The same issue for RHEL 8 is this one:
https://bugzilla.redhat.com/show_bug.cgi?id=2180462
Comment 2 Florian Weimer 2023-06-13 09:03:44 UTC 
In particular, this should include a backport of this commit to benefit TDX environments as they exist today:

commit ed2f9dc9420c4c61436328778a70459d0a35556a
Author: Noah Goldstein <goldstein.w.n>
Date:   Mon May 8 22:10:20 2023 -0500

    x86: Use 64MB as nt-store threshold if no cacheinfo [BZ #30429]
    
    If `non_temporal_threshold` is below `minimum_non_temporal_threshold`,
    it almost certainly means we failed to read the systems cache info.
    
    In this case, rather than defaulting the minimum correct value, we
    should default to a value that gets at least reasonable
    performance. 64MB is chosen conservatively to be at the very high
    end. This should never cause non-temporal stores when, if we had read
    cache info, we wouldn't have otherwise.
    Reviewed-by: Florian Weimer <fweimer>
Comment 15 errata-xmlrpc 2023-11-07 08:37:51 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-2023:6582
Note You need to log in before you can comment on or make changes to this bug.