[Bug] Glibc: performance improvement patches

[quanxian]

Description:

Intel’s new request – for performance related patches that need to be picked up as part of one the Ubuntu 16.04 LTS family releases and Ubuntu 17.10:

Glibc 2.23 needs the first 2 patches on hjl/pr21258/2.23 branch:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=shortlog;h=refs/heads/hjl/pr21258/2.23
Patches: Address transition penalty when SSE instructions are mixed with 256-bit AVX or 512-bit AVX512 load instructions.

Target Release: TBD

[Steve Langasek (vorlon)]

This is documented upstream as fixed in glibc 2.26, which is the version we will ship in artful; therefore marking as resolved for the devel series.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Steve Langasek (vorlon)]

This is fixed in newer releases of Ubuntu, including 2 LTSes that have been released since this bug was filed. We have not found capacity to land this in Ubuntu 16.04 in 2.5 years; I'm therefore marking this wontfix which is more realistic. Users will get improved performance by upgrading to Ubuntu 18.04 or Ubuntu 20.04.