Re: [PATCH v2 5/5] powerpc: Remove -mno-sched-epilog

On Fri, Sep 14, 2018 at 2:56 PM Segher Boessenkool
[off-list ref] wrote:

On Sat, Sep 15, 2018 at 06:43:05AM +1000, Nicholas Piggin wrote:

quoted

On Fri, 14 Sep 2018 11:03:38 -0700
Nick Desaulniers [off-list ref] wrote:

quoted

On Thu, Sep 13, 2018 at 9:07 PM Joel Stanley [off-list ref] wrote:

quoted

Last time this was proposed there was an issue reported:

 https://lists.ozlabs.org/pipermail/linuxppc-dev/2014-September/121214.html

Heh, did PASemi sell boxes? Interesting, I'll have to read up on my history.

On Thu, Sep 13, 2018 at 10:06 PM Nicholas Piggin [off-list ref] wrote:

quoted

I don't think we can remove it completely because up to at least 4.6
maybe 4.8 has problems.

I have a few patches lying around I started looking at this... I'll
send them.

Yeah, it's too bad the link above doesn't mention gcc version.

The gcc bugreport mentions fixing the bug in
7563dc64585324f443f5ac107eb6d89ee813a2d2, not sure how to check what
release version of gcc that is? (Do they tag releases?)

I'm not sure, that's not in my gcc tree AFAIKS.

This is a git hash in the kernel tree.

quoted

quoted

Nick, do you have a test case or more context about this still being
an issue in gcc 4.8? (maybe I should wait for your patch series?)

Sorry I forgot to cc you. This has links to some of the sched
epilog bugs.

https://marc.info/?l=linuxppc-embedded&m=153690223909654&w=2

Cool, cc me on the thread if you'd like me to add my reviewed-by tag
visibly on the thread.

PR44199 was backported to 4.4 and PR52828 is fixed in 4.8.

Are those GCC versions? If so, what does that mean for the users of
the many GCC releases between 4.4 and 4.8?

-- 
Thanks,
~Nick Desaulniers