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On Fri, 14 Sep 2018, Florian Weimer wrote: > On 09/14/2018 02:50 PM, Thomas Gleixner wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different copy of the same code. > > > > Especially the extended switch case is problematic as the compiler

On Fri, Sep 14, 2018 at 02:56:46PM +0200, Florian Weimer wrote: > On 09/14/2018 02:50 PM, Thomas Gleixner wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different copy of the same code. > > > > Especially the extended switch case is

On Fri, 14 Sep 2018, Florian Weimer wrote: > On 09/14/2018 03:05 PM, Thomas Gleixner wrote: > > On Fri, 14 Sep 2018, Florian Weimer wrote: > > > > > On 09/14/2018 02:50 PM, Thomas Gleixner wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > > > implementation, which extended the clockid switch case and added yet

> On Oct 3, 2018, at 5:01 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > > Andy Lutomirski <luto at amacapital.net> writes: > >>> On Oct 3, 2018, at 2:22 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: >>> >>> Andy Lutomirski <luto at kernel.org> writes: >>> >>>> Hi Vitaly, Paolo, Radim, etc.,

On Thu, Oct 04, 2018 at 09:54:45AM +0200, Vitaly Kuznetsov wrote: > I was hoping to hear this from you :-) If I am to suggest how we can > move forward I'd propose: > - Check if pure TSC can be used on SkyLake+ systems (where TSC scaling > is supported). > - Check if non-masterclock mode is still needed. E.g. HyperV's TSC page > clocksource is a single page for the whole

On 04/10/2018 09:54, Vitaly Kuznetsov wrote: > - Check if pure TSC can be used on SkyLake+ systems (where TSC scaling > is supported). Not if you want to migrate to pre-Skylake systems. > - Check if non-masterclock mode is still needed. E.g. HyperV's TSC page > clocksource is a single page for the whole VM, not a per-cpu thing. Can > we think that all the buggy hardware is

On Thu, Oct 04, 2018 at 07:00:45AM -0700, Andy Lutomirski wrote: > > On Oct 4, 2018, at 1:11 AM, Peter Zijlstra <peterz at infradead.org> wrote: > > > >> On Thu, Oct 04, 2018 at 09:54:45AM +0200, Vitaly Kuznetsov wrote: > >> I was hoping to hear this from you :-) If I am to suggest how we can > >> move forward I'd propose: > >> - Check if

For better or for worse, I'm trying to understand this code. So far, I've come up with this patch: https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso-tglx&id=14fd71e12b1c4492a06f368f75041f263e6862bf Is it correct, or am I missing some subtlety?

On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > > For better or for worse, I'm trying to understand this code. So far, > > I've come up with this patch: > > > >

On Mon, Oct 8, 2018 at 8:27 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Sat, Oct 06, 2018 at 03:28:05PM -0700, Andy Lutomirski wrote: > > On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > > > > For better or for worse,

On Tue, Oct 9, 2018 at 8:28 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Mon, Oct 08, 2018 at 10:38:22AM -0700, Andy Lutomirski wrote: > > On Mon, Oct 8, 2018 at 8:27 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > I read the comment three more times and even dug through the git > > history. It seems like what you're saying is that,

On Thu, Oct 11, 2018 at 3:28 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Tue, Oct 09, 2018 at 01:09:42PM -0700, Andy Lutomirski wrote: > > On Tue, Oct 9, 2018 at 8:28 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > On Mon, Oct 08, 2018 at 10:38:22AM -0700, Andy Lutomirski wrote: > > > > On Mon, Oct 8, 2018 at 8:27

Hi Vitaly, Paolo, Radim, etc., On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > implementation, which extended the clockid switch case and added yet > another slightly different copy of the same code. > > Especially the extended switch case is problematic as the compiler

On Fri, Sep 14, 2018 at 2:52 PM Thomas Gleixner <tglx at linutronix.de> wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > implementation, which extended the clockid switch case and added yet > another slightly different copy of the same code. > > Especially the extended switch case is problematic as the compiler tends to > generate a jump

On Fri, 14 Sep 2018, Arnd Bergmann wrote: > On Fri, Sep 14, 2018 at 2:52 PM Thomas Gleixner <tglx at linutronix.de> wrote: > A couple of architectures (s390, ia64, riscv, powerpc, arm64) > implement the vdso as assembler code at the moment, so they > won't be as easy to consolidate (other than outright replacing all > the code). > > The other five: >

On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > Hi Vitaly, Paolo, Radim, etc., > > > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > > > Matt attempted to add CLOCK_TAI support to the VDSO

On Wed, 3 Oct 2018, Andy Lutomirski wrote: > > On Oct 3, 2018, at 5:01 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > > Not all Hyper-V hosts support reenlightenment notifications (and, if I'm > > not mistaken, you need to enable nesting for the VM to get the feature - > > and most VMs don't have this) so I think we'll have to keep Hyper-V >

On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > For better or for worse, I'm trying to understand this code. So far, > I've come up with this patch: > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso-tglx&id=14fd71e12b1c4492a06f368f75041f263e6862bf > > Is it correct, or am I missing some subtlety? The master

On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > For better or for worse, I'm trying to understand this code. So far, > I've come up with this patch: > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso-tglx&id=14fd71e12b1c4492a06f368f75041f263e6862bf > > Is it correct, or am I missing some subtlety? The master

On Thu, Oct 4, 2018 at 9:43 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Wed, Oct 03, 2018 at 03:32:08PM -0700, Andy Lutomirski wrote: > > On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > > > Hi Vitaly, Paolo, Radim,