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. Thanks, tglx
