similar to: [PATCH v2 0/3] x86/vdso: Add Hyper-V TSC page clocksource support

Hi, Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. Implemented the required support. Simple sysbench test shows the following results: Before: # time sysbench --test=memory --max-requests=500000 run ... real 1m22.618s user 0m50.193s sys 0m32.268s After: # time sysbench --test=memory

Hi, Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. Implemented the required support. Simple sysbench test shows the following results: Before: # time sysbench --test=memory --max-requests=500000 run ... real 1m22.618s user 0m50.193s sys 0m32.268s After: # time sysbench --test=memory

Hi, merge window is about to close so I hope it's OK to make another try here. Changes since v2: - Add explicit READ_ONCE() to not rely on 'volatile' [Andy Lutomirski] - rdtsc() -> rdtsc_ordered() [Andy Lutomirski] - virt_rmb() -> smp_rmb() [Thomas Gleixner, Andy Lutomirski] Thomas, Andy, it seems the only blocker for the series was the ambiguity with TSC page read algorithm.

Hi, merge window is about to close so I hope it's OK to make another try here. Changes since v2: - Add explicit READ_ONCE() to not rely on 'volatile' [Andy Lutomirski] - rdtsc() -> rdtsc_ordered() [Andy Lutomirski] - virt_rmb() -> smp_rmb() [Thomas Gleixner, Andy Lutomirski] Thomas, Andy, it seems the only blocker for the series was the ambiguity with TSC page read algorithm.

Hi, Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. I implemented the required support re-using pvclock_page VVAR. Simple sysbench test shows the following results: Before: # time sysbench --test=memory --max-requests=500000 run ... real 1m22.618s user 0m50.193s sys 0m32.268s After: # time sysbench

Hi, Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. I implemented the required support re-using pvclock_page VVAR. Simple sysbench test shows the following results: Before: # time sysbench --test=memory --max-requests=500000 run ... real 1m22.618s user 0m50.193s sys 0m32.268s After: # time sysbench

On Wed, Feb 8, 2017 at 9:07 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol > defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the > required support re-using pvclock_page VVAR as VCLOCK_PVCLOCK is mutually > exclusive with VCLOCK_HVCLOCK at run time. > > Signed-off-by:

On Wed, Feb 8, 2017 at 9:07 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol > defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the > required support re-using pvclock_page VVAR as VCLOCK_PVCLOCK is mutually > exclusive with VCLOCK_HVCLOCK at run time. > > Signed-off-by:

On Thu, 9 Feb 2017, Vitaly Kuznetsov wrote: > +#ifdef CONFIG_HYPERV_TSCPAGE > +static notrace u64 vread_hvclock(int *mode) > +{ > + const struct ms_hyperv_tsc_page *tsc_pg = > + (const struct ms_hyperv_tsc_page *)&hvclock_page; > + u64 sequence, scale, offset, current_tick, cur_tsc; > + > + while (1) { > + sequence = READ_ONCE(tsc_pg->tsc_sequence); > + if

On Thu, 9 Feb 2017, Vitaly Kuznetsov wrote: > +#ifdef CONFIG_HYPERV_TSCPAGE > +static notrace u64 vread_hvclock(int *mode) > +{ > + const struct ms_hyperv_tsc_page *tsc_pg = > + (const struct ms_hyperv_tsc_page *)&hvclock_page; > + u64 sequence, scale, offset, current_tick, cur_tsc; > + > + while (1) { > + sequence = READ_ONCE(tsc_pg->tsc_sequence); > + if

The actual code looks fine, but the style police will not like you. { should be at start of line on functions. And #else should be at start of line, But maybe this was just more of exchange mangling the mail. -----Original Message----- From: Vitaly Kuznetsov [mailto:vkuznets at redhat.com] Sent: Thursday, February 9, 2017 6:11 AM To: x86 at kernel.org; Andy Lutomirski <luto at

The actual code looks fine, but the style police will not like you. { should be at start of line on functions. And #else should be at start of line, But maybe this was just more of exchange mangling the mail. -----Original Message----- From: Vitaly Kuznetsov [mailto:vkuznets at redhat.com] Sent: Thursday, February 9, 2017 6:11 AM To: x86 at kernel.org; Andy Lutomirski <luto at

On Thu, Feb 9, 2017 at 12:45 PM, KY Srinivasan <kys at microsoft.com> wrote: > > >> -----Original Message----- >> From: Thomas Gleixner [mailto:tglx at linutronix.de] >> Sent: Thursday, February 9, 2017 9:08 AM >> To: Vitaly Kuznetsov <vkuznets at redhat.com> >> Cc: x86 at kernel.org; Andy Lutomirski <luto at amacapital.net>; Ingo Molnar

On Thu, Feb 9, 2017 at 12:45 PM, KY Srinivasan <kys at microsoft.com> wrote: > > >> -----Original Message----- >> From: Thomas Gleixner [mailto:tglx at linutronix.de] >> Sent: Thursday, February 9, 2017 9:08 AM >> To: Vitaly Kuznetsov <vkuznets at redhat.com> >> Cc: x86 at kernel.org; Andy Lutomirski <luto at amacapital.net>; Ingo Molnar

As a preparation to making Hyper-V TSC page suitable for vDSO move the TSC page reading logic to asm/mshyperv.h. While on it, do the following - Document the reading algorithm. - Simplify the code a bit. - Add explicit READ_ONCE() to not rely on 'volatile'. - Add explicit barriers to prevent re-ordering (we need to read sequence strictly before and after) - Use mul_u64_u64_shr() instead

Minor coding comments > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index d324dce..4ff25436 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -178,6 +178,56 @@ void hyperv_cleanup(void); > #endif > #ifdef CONFIG_HYPERV_TSCPAGE > struct ms_hyperv_tsc_page *hv_get_tsc_page(void); > +static

Minor coding comments > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index d324dce..4ff25436 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -178,6 +178,56 @@ void hyperv_cleanup(void); > #endif > #ifdef CONFIG_HYPERV_TSCPAGE > struct ms_hyperv_tsc_page *hv_get_tsc_page(void); > +static

Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the required support by adding hvclock_page VVAR. Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com> --- arch/x86/entry/vdso/vclock_gettime.c | 36 +++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 3 ++-

To use Hyper-V TSC page clocksource from vDSO we need to make tsc_pg available. Implement hv_get_tsc_page() and add CONFIG_HYPERV_TSCPAGE to make #ifdef-s simple. Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com> --- arch/x86/hyperv/hv_init.c | 9 +++++++-- arch/x86/include/asm/mshyperv.h | 8 ++++++++ drivers/hv/Kconfig | 3 +++ 3 files changed, 18 insertions(+),

Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the required support re-using pvclock_page VVAR as VCLOCK_PVCLOCK is mutually exclusive with VCLOCK_HVCLOCK at run time. Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com> --- arch/x86/entry/vdso/vclock_gettime.c | 48