On Wed, 21 Aug 2019, Thomas Gleixner wrote: > On Wed, 21 Aug 2019, Vitaly Kuznetsov wrote: > > > There is no particular reason to not enable TSC page clocksource > > on 32-bit. mul_u64_u64_shr() is available and despite the increased > > computational complexity (compared to 64bit) TSC page is still a huge > > win compared to MSR-based clocksource. > > > > In-kernel reads: > > MSR based clocksource: 3361 cycles > > TSC page clocksource: 49 cycles > > > > Reads from userspace (unilizing vDSO in case of TSC page): > > MSR based clocksource: 5664 cycles > > TSC page clocksource: 131 cycles > > > > Enabling TSC page on 32bits allows us to get rid of CONFIG_HYPERV_TSCPAGE > > s/allows us/allows/ > > > as it is now not any different from CONFIG_HYPERV_TIMER. > > > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > > --- > > arch/x86/include/asm/vdso/gettimeofday.h | 6 +++--- > > drivers/clocksource/hyperv_timer.c | 11 ----------- > > drivers/hv/Kconfig | 3 --- > > include/clocksource/hyperv_timer.h | 6 ++---- > > 4 files changed, 5 insertions(+), 21 deletions(-) > > Really nice cleanup as a side effect of adding functionality. That said, could you please rebase that on git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/core as I just applied the TSC page patches there and this conflicts left and right. Thanks, tglx
