On Mon, May 03, 2021 at 10:41:45AM -0700, Linus Torvalds wrote:
> It would be lovely if somebody also took a look at some of the other
> zlib code, like inflate.c itself. But some of that code has rather
> subtle changes for things like s390 hardware support, and we have
> thihngs like our fallthro
On 5/3/21 10:41 AM, Linus Torvalds wrote:
> On Fri, Apr 30, 2021 at 1:46 PM Vineet Gupta
> wrote:
>> I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
>> causing wrong codegen.
> So it does seem to be a gcc bug or at least mis-feature where gcc gets
> the aliasing decision wro
On Fri, Apr 30, 2021 at 1:46 PM Vineet Gupta wrote:
>
> I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
> causing wrong codegen.
So it does seem to be a gcc bug or at least mis-feature where gcc gets
the aliasing decision wrong when vectorizing the code.
That said, the fact
Hello.
On Fri, Apr 30, 2021 at 03:06:30PM -0700, Linus Torvalds wrote:
> On Fri, Apr 30, 2021 at 1:46 PM Vineet Gupta
> wrote:
> >
> > I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
> > causing wrong codegen.
>
> I'd be more than happy to just disable CC_OPTIMIZE_FOR_PERF
On 4/30/21 3:06 PM, Linus Torvalds wrote:
> On Fri, Apr 30, 2021 at 1:46 PM Vineet Gupta
> wrote:
>>
>> I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
>> causing wrong codegen.
>
> I'd be more than happy to just disable CC_OPTIMIZE_FOR_PERFORMANCE_O3
> entirely.
>
> The
Hi,
I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
causing wrong codegen.
Config needs to have initramfs + gzip compressed.
CONFIG_HAVE_KERNEL_GZIP=y
CONFIG_KERNEL_GZIP=y
CONFIG_DECOMPRESS_GZIP=y
CONFIG_INITRAMFS_COMPRESSION_GZIP=y
lib
On Fri, Apr 30, 2021 at 3:44 PM Vineet Gupta wrote:
>
> I agree that -O2 is default, but we've had -O3 default for ARC kernel
> forever, since last decade seriously. The reason I turned it on back
> then was upside of 10% performance improvement on select LMBench numbers
> on hardware at the time
On Fri, Apr 30, 2021 at 1:46 PM Vineet Gupta wrote:
>
> I've hit a mainline gcc 10.2 (also gcc 9.3) bug which triggers at -O3
> causing wrong codegen.
I'd be more than happy to just disable CC_OPTIMIZE_FOR_PERFORMANCE_O3 entirely.
The advantages are very questionable - with a lot of the optimiza
