On 2018-08-21 8:50 AM, Helge Deller wrote:
On 21.08.2018 13:51, Rolf Eike Beer wrote:
I switched from 4.17.3 to 4.18.0 on my C8000 on Friday. Since then I see a massive slowdown in my CDash builds (building CMake, libarchive, Qsmtp). From what I see this seems not to be related to any change in the projects:
You could try to revert the memory barrier patches:
* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fedb8da96355f5f64353625bf96dc69423ad1826
and/or the default-enabled CONFIG_MLONGCALLS option:
* http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=66509a276c8c1d19ee3f661a41b418d101c57d29
I've noticed the slow down as well. The long call option will
definitely slow things.
I would guess that it's the sync in the TLB unlock code that's slowing
things. Maybe we don't care about
races in this code.
Timing before:
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 4.7 Aug 17, 2018 - 13:37
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 4.8 Aug 17, 2018 - 11:19
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 4.9 Aug 17, 2018 - 09:06
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 5 Aug 17, 2018 - 06:50
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 6 Aug 17, 2018 - 04:25
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 7 Aug 17, 2018 - 00:54
Timing after:
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 4.9 Aug 20, 2018 - 13:02:06
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 5 Aug 20, 2018 - 10:04:10
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 6 Aug 20, 2018 - 06:51
pioneer.sf-tec.de Gentoo HPPA C8000 GCC 7 Aug 20, 2018 - 02:08
Why such a big difference in times between gcc versions? I think it
would be useful to
use time to compare system times.
Dave
--
John David Anglin dave.anglin@xxxxxxxx
