ORC Unwinder For Linux 4.14, Boosts Kernel Performance By Disabling Frame Pointers

[phoronix]

Phoronix: ORC Unwinder For Linux 4.14, Boosts Kernel Performance By Disabling Frame Pointers

Ingo Molnar submitted the Linux x86 Assembly updates today for the 4.14 merge window. What's interesting with the x86/asm code changes is the introduction of the ORC Unwinder...

http://www.phoronix.com/scan.php?page=news_item&px=ORC-Unwinder-Linux-4.14

[jabl]

From the pull request:

Remove lguest support: its intended role was that of a temporary proof of
concept for virtualization, plus its removal will enable the reduction
(removal) of the paravirt API as well, so Rusty agreed to its removal.
(Juergen Gross)

So am I reading this right that they are planning to completely remove paravirtualization support? Sure, hw virt support is fairly common nowadays, but usually they are pretty conservative about removing features that someone might still depend on?

[rubdos]

From the pull request:



So am I reading this right that they are planning to completely remove paravirtualization support? Sure, hw virt support is fairly common nowadays, but usually they are pretty conservative about removing features that someone might still depend on?

I usually presume these people run a LTS kernel on Red Hat/SuSE.

[arjan_intel]

From the pull request:



So am I reading this right that they are planning to completely remove paravirtualization support? Sure, hw virt support is fairly common nowadays, but usually they are pretty conservative about removing features that someone might still depend on?

the way I read is that the plan is to minimize paravirt to the absolute minimal possible. Paravirt is pretty expensive in terms of how invasive it is to the code (never mind the performance impact of it)

[ext73]

My kernel builds ... as always

CONFIG_FRAME_POINTER is not set

[NeteXt'73]

[starshipeleven]

I usually presume these people run a LTS kernel on Red Hat/SuSE.

I'm pretty positive that RHEL/SLES are all run on hardware that supports hw virtualization already.

I mean even potatoes have hw virtualization support nowadays.

[andrei_me]

Does ORC acronym have any meaning besides joking with dwarf?

[TumultuousUnicorn]

$ uname -a
Linux localhost 4.12.10-1-ck-sandybridge #1 SMP PREEMPT Wed Aug 30 15:49:36 EDT 2017 x86_64 GNU/Linux

$ zgrep CONFIG_FRAME_POINTER /proc/config.gz
CONFIG_FRAME_POINTER=y

Ah. True story on Arch.

[franglais125]

It is not set by default on Debian Stable.

# CONFIG_FRAME_POINTER is not set

[mattst88]

Does ORC acronym have any meaning besides joking with dwarf?

I don't know for sure, but I doubt it.

In case you aren't aware, the name DWARF is itself a joke based on the ELF binary format. https://en.wikipedia.org/wiki/DWARF