Public bug reported:

Initially we have taken care to only enable the default 64 bit cpu 
(march=x86_84 is the default) and SSE3 because it could not made to work 
without.
SSE3 was part of the MIR in bug 1492186.

It seems since then the build system sneaked in an optimization that we didn't 
intend.
See 
https://launchpadlibrarian.net/382624532/buildlog_ubuntu-bionic-amd64.dpdk_17.11.3-3~ubuntu0.18.04_BUILDING.txt.gz

There is -march=corei7 set by the DPDK build system.

This leads to a surely interesting discussion, we are now faced with:
- DPDK would not work (at least well) on processors not having the new CPU 
features
- Many people asked us to enable an optimization like that and we refused for 
"compatibility"
- it is that way since Bionic was released and we had no complaint at all

Therefore maybe the right thing is a doc fix that this has a higher CPU 
requirement than usual.
We do so for SSE3 already.

OTOH if we switch it off back to compatibility I'm sure some people will
hit performance regressions.

Decision:
- switch back to Ubuntu default of x86_64 (+sse3)
- keep DPDK project default bas level (=corei7) and update documentation

I'll discuss that in the Team and the deb_dpdk project

** Affects: dpdk (Ubuntu)
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1801736

Title:
  DPDK is build with march=corei7

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/dpdk/+bug/1801736/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to