search for: vclock_gettim

...ce depends heavily on the micro architecture and the compiler. Changes vs. V1: - Fix the VCLOCK_MAX sanity check - Remove the magic clock masking and extend the storage array Thanks, tglx 8<------------------- arch/x86/Kconfig | 1 arch/x86/entry/vdso/vclock_gettime.c | 199 ++++++++------------------------ arch/x86/entry/vsyscall/vsyscall_gtod.c | 55 ++++---- arch/x86/include/asm/vgtod.h | 42 +++--- arch/x86/kernel/time.c | 22 +++ include/linux/clocksource.h | 5 kernel/time/Kconfig...

...: # time sysbench --test=memory --max-requests=500000 run ... real 0m50.218s user 0m50.171s sys 0m0.016s So it seems it is worth it. What do you think? Vitaly Kuznetsov (2): hyperv: implement hv_get_tsc_page() x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method arch/x86/entry/vdso/vclock_gettime.c | 48 ++++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vma.c | 26 +++++++++++++------ arch/x86/hyperv/hv_init.c | 8 ++++++ arch/x86/include/asm/clocksource.h | 3 ++- arch/x86/include/asm/mshyperv.h | 8 ++++++ drivers/hv/Kconfig | 5 +...

...: # time sysbench --test=memory --max-requests=500000 run ... real 0m50.218s user 0m50.171s sys 0m0.016s So it seems it is worth it. What do you think? Vitaly Kuznetsov (2): hyperv: implement hv_get_tsc_page() x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method arch/x86/entry/vdso/vclock_gettime.c | 48 ++++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vma.c | 26 +++++++++++++------ arch/x86/hyperv/hv_init.c | 8 ++++++ arch/x86/include/asm/clocksource.h | 3 ++- arch/x86/include/asm/mshyperv.h | 8 ++++++ drivers/hv/Kconfig | 5 +...

...y 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 ++++++++++++++++++++++++++++++++++++ > arch/x86/entry/vdso/vma.c | 26 +++++++++++++------ > arch/x86/hyperv/hv_init.c | 3 +++ > arch/x86/include/asm/clocksource.h | 3 ++- > 4 files changed, 72 insertions(+), 8 deletions(-) > > diff --git a/arc...

...y 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 ++++++++++++++++++++++++++++++++++++ > arch/x86/entry/vdso/vma.c | 26 +++++++++++++------ > arch/x86/hyperv/hv_init.c | 3 +++ > arch/x86/include/asm/clocksource.h | 3 ++- > 4 files changed, 72 insertions(+), 8 deletions(-) > > diff --git a/arc...

...which at the end all together gain a few cycles performance or at least stay on par with todays code. The resulting performance depends heavily on the micro architecture and the compiler. Thanks, tglx 8<------------------- arch/x86/Kconfig | 1 arch/x86/entry/vdso/vclock_gettime.c | 199 ++++++++------------------------ arch/x86/entry/vsyscall/vsyscall_gtod.c | 55 ++++---- arch/x86/include/asm/vgtod.h | 46 ++++--- arch/x86/kernel/time.c | 22 +++ include/linux/clocksource.h | 5 kernel/time/Kconfig...

...which at the end all together gain a few cycles performance or at least stay on par with todays code. The resulting performance depends heavily on the micro architecture and the compiler. Thanks, tglx 8<------------------- arch/x86/Kconfig | 1 arch/x86/entry/vdso/vclock_gettime.c | 199 ++++++++------------------------ arch/x86/entry/vsyscall/vsyscall_gtod.c | 55 ++++---- arch/x86/include/asm/vgtod.h | 46 ++++--- arch/x86/kernel/time.c | 22 +++ include/linux/clocksource.h | 5 kernel/time/Kconfig...

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

...wever, 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 ++++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vma.c | 26 +++++++++++++------ arch/x86/hyperv/hv_init.c | 3 +++ arch/x86/include/asm/clocksource.h | 3 ++- 4 files changed, 72 insertions(+), 8 deletions(-) diff --git a/arch/x86/entry/vdso/vclock_getti...

...return current_tick; > > That sequence stuff lacks still a sensible explanation. It's fundamentally > different from the sequence counting we do in the kernel, so documentation > for it is really required. Sure, do you think the following would do? diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 4af10b4..886b600 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -154,6 +154,22 @@ static notrace u64 vread_hvclock(int *mode) (const struct ms_hyperv_tsc_page *)&hvclock_page;...

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 ++- arch/x86/entry/vdso/vdso2c.c | 3 +++ arch/x86/entry/vdso/vma.c | 7 +++++++ arch/x86/hyperv/hv_init.c | 3 +++ arch/x86/include/asm/clocksource.h | 3 ++- arch/x86/...

...inutronix.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: > arch/x86/entry/vdso/vclock_gettime.c > arch/sparc/vdso/vclock_gettime.c > arch/nds32/kernel/vdso/gettimeofday.c > arch/mips/vdso/gettimeofday.c > arch/arm/vdso/vgettimeofday.c > > are basically all minor variations of the same code base and could be > consolidated to some degree. > Any suggestions here? Shou...

...id 11 which results in 3 when masked with 0x3 Add the mask to the basetime array lookup and set up the CLOCK_TAI base time in update_vsyscall(). The performance impact of the mask operation is within the noise. Signed-off-by: Thomas Gleixner <tglx at linutronix.de> --- arch/x86/entry/vdso/vclock_gettime.c | 2 +- arch/x86/entry/vsyscall/vsyscall_gtod.c | 4 ++++ arch/x86/include/asm/vgtod.h | 6 +++++- 3 files changed, 10 insertions(+), 2 deletions(-) --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -140,7 +140,7 @@ notrace static in...

...s generates horrible code. Doing it at the call site is much better and gains a few cycles both for TSC and pvclock. Caveat: This adds the comparison to the hyperv vclock as well, but I have no way to test that. Signed-off-by: Thomas Gleixner <tglx at linutronix.de> --- arch/x86/entry/vdso/vclock_gettime.c | 39 ++++++----------------------------- 1 file changed, 7 insertions(+), 32 deletions(-) --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -76,9 +76,8 @@ static notrace const struct pvclock_vsys static notrace u64 vread_pvclock(void) { const struct...

...CK -> HYPERV_TSCPAGE to avoid the ambiguity. I'm also going to try to optimize mul_u64_u64_shr() for 32bit but this can be split from this series I guess. Vitaly Kuznetsov (2): hyperv: implement hv_get_tsc_page() x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method arch/x86/entry/vdso/vclock_gettime.c | 36 +++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 3 ++- arch/x86/entry/vdso/vdso2c.c | 3 +++ arch/x86/entry/vdso/vma.c | 7 +++++++ arch/x86/hyperv/hv_init.c | 12 ++++++++++-- arch/x86/include/asm/clocksource.h | 3 ++-...

...CK -> HYPERV_TSCPAGE to avoid the ambiguity. I'm also going to try to optimize mul_u64_u64_shr() for 32bit but this can be split from this series I guess. Vitaly Kuznetsov (2): hyperv: implement hv_get_tsc_page() x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method arch/x86/entry/vdso/vclock_gettime.c | 36 +++++++++++++++++++++++++++++++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 3 ++- arch/x86/entry/vdso/vdso2c.c | 3 +++ arch/x86/entry/vdso/vma.c | 7 +++++++ arch/x86/hyperv/hv_init.c | 12 ++++++++++-- arch/x86/include/asm/clocksource.h | 3 ++-...

...l(). That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere to assert that this actually works? > > The performance impact of the mask operation is within the noise. > > Signed-off-by: Thomas Gleixner <tglx at linutronix.de> > --- > arch/x86/entry/vdso/vclock_gettime.c | 2 +- > arch/x86/entry/vsyscall/vsyscall_gtod.c | 4 ++++ > arch/x86/include/asm/vgtod.h | 6 +++++- > 3 files changed, 10 insertions(+), 2 deletions(-) > > --- a/arch/x86/entry/vdso/vclock_gettime.c > +++ b/arch/x86/entry/vdso/vclock_gettime.c > @@ -1...

...l(). That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere to assert that this actually works? > > The performance impact of the mask operation is within the noise. > > Signed-off-by: Thomas Gleixner <tglx at linutronix.de> > --- > arch/x86/entry/vdso/vclock_gettime.c | 2 +- > arch/x86/entry/vsyscall/vsyscall_gtod.c | 4 ++++ > arch/x86/include/asm/vgtod.h | 6 +++++- > 3 files changed, 10 insertions(+), 2 deletions(-) > > --- a/arch/x86/entry/vdso/vclock_gettime.c > +++ b/arch/x86/entry/vdso/vclock_gettime.c > @@ -1...

...clocksource to arch/x86/hyperv/hv_init.c, this is currently present in Greg's char-misc-next tree. Vitaly Kuznetsov (3): x86/hyperv: implement hv_get_tsc_page() x86/hyperv: move TSC reading method to asm/mshyperv.h x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method arch/x86/entry/vdso/vclock_gettime.c | 24 +++++++++++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 3 +- arch/x86/entry/vdso/vdso2c.c | 3 ++ arch/x86/entry/vdso/vma.c | 7 +++++ arch/x86/hyperv/hv_init.c | 48 +++++++++-------------------- arch/x86/include/asm/clocksource.h | 3 +- arch/x86...