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 (utilizing vDSO in case of TSC page):
MSR based clocksource: 5664 cycles
TSC page clocksource: 131 cycles
Enabling TSC page on 32bits allows to get rid of CONFIG_HYPERV_TSCPAGE as
it is now not any different from CONFIG_HYPERV_TIMER.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lkml.kernel.org/r/20190822083630.17059-1-vkuznets@redhat.com
__attribute__((visibility("hidden")));
#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
+#ifdef CONFIG_HYPERV_TIMER
extern struct ms_hyperv_tsc_page hvclock_page
__attribute__((visibility("hidden")));
#endif
}
#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
+#ifdef CONFIG_HYPERV_TIMER
static u64 vread_hvclock(void)
{
return hv_read_tsc_page(&hvclock_page);
return vread_pvclock();
}
#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
+#ifdef CONFIG_HYPERV_TIMER
if (clock_mode == VCLOCK_HVCLOCK) {
barrier();
return vread_hvclock();
struct clocksource *hyperv_cs;
EXPORT_SYMBOL_GPL(hyperv_cs);
-#ifdef CONFIG_HYPERV_TSCPAGE
-
static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-#endif
static u64 notrace read_hv_clock_msr(struct clocksource *arg)
{
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-#ifdef CONFIG_HYPERV_TSCPAGE
static bool __init hv_init_tsc_clocksource(void)
{
u64 tsc_msr;
return true;
}
-#else
-static bool __init hv_init_tsc_clocksource(void)
-{
- return false;
-}
-#endif
-
void __init hv_init_clocksource(void)
{
config HYPERV_TIMER
def_bool HYPERV
-config HYPERV_TSCPAGE
- def_bool HYPERV && X86_64
-
config HYPERV_UTILS
tristate "Microsoft Hyper-V Utilities driver"
depends on HYPERV && CONNECTOR && NLS
extern void hv_stimer_global_cleanup(void);
extern void hv_stimer0_isr(void);
-#if IS_ENABLED(CONFIG_HYPERV)
+#ifdef CONFIG_HYPERV_TIMER
extern struct clocksource *hyperv_cs;
extern void hv_init_clocksource(void);
-#endif /* CONFIG_HYPERV */
-#ifdef CONFIG_HYPERV_TSCPAGE
extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
static inline notrace u64
return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc);
}
-#else /* CONFIG_HYPERV_TSC_PAGE */
+#else /* CONFIG_HYPERV_TIMER */
static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return NULL;
{
return U64_MAX;
}
-#endif /* CONFIG_HYPERV_TSCPAGE */
+#endif /* CONFIG_HYPERV_TIMER */
#endif