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[89.176.161.20]) by smtp.gmail.com with ESMTPSA id j16sm18795169wrp.62.2019.08.21.02.56.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2019 02:56:53 -0700 (PDT) From: Vitaly Kuznetsov To: linux-hyperv@vger.kernel.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Daniel Lezcano , Michael Kelley , Tianyu Lan , Peter Zijlstra Subject: [PATCH] x86/hyper-v: enable TSC page clocksource on 32bit Date: Wed, 21 Aug 2019 11:56:50 +0200 Message-Id: <20190821095650.1841-1-vkuznets@redhat.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 as it is now not any different from CONFIG_HYPERV_TIMER. Signed-off-by: Vitaly Kuznetsov --- 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(-) diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h index ba71a63cdac4..e9ee139cf29e 100644 --- a/arch/x86/include/asm/vdso/gettimeofday.h +++ b/arch/x86/include/asm/vdso/gettimeofday.h @@ -51,7 +51,7 @@ extern struct pvclock_vsyscall_time_info pvclock_page __attribute__((visibility("hidden"))); #endif -#ifdef CONFIG_HYPERV_TSCPAGE +#ifdef CONFIG_HYPERV_TIMER extern struct ms_hyperv_tsc_page hvclock_page __attribute__((visibility("hidden"))); #endif @@ -228,7 +228,7 @@ static u64 vread_pvclock(void) } #endif -#ifdef CONFIG_HYPERV_TSCPAGE +#ifdef CONFIG_HYPERV_TIMER static u64 vread_hvclock(void) { return hv_read_tsc_page(&hvclock_page); @@ -251,7 +251,7 @@ static inline u64 __arch_get_hw_counter(s32 clock_mode) return vread_pvclock(); } #endif -#ifdef CONFIG_HYPERV_TSCPAGE +#ifdef CONFIG_HYPERV_TIMER if (clock_mode == VCLOCK_HVCLOCK) { barrier(); return vread_hvclock(); diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index ba2c79e6a0ee..b6083faab540 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -212,8 +212,6 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup); struct clocksource *hyperv_cs; EXPORT_SYMBOL_GPL(hyperv_cs); -#ifdef CONFIG_HYPERV_TSCPAGE - static struct ms_hyperv_tsc_page *tsc_pg; struct ms_hyperv_tsc_page *hv_get_tsc_page(void) @@ -244,7 +242,6 @@ static struct clocksource hyperv_cs_tsc = { .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; -#endif static u64 notrace read_hv_sched_clock_msr(void) { @@ -271,7 +268,6 @@ static struct clocksource hyperv_cs_msr = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; -#ifdef CONFIG_HYPERV_TSCPAGE static bool __init hv_init_tsc_clocksource(void) { u64 tsc_msr; @@ -306,13 +302,6 @@ static bool __init hv_init_tsc_clocksource(void) sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ); return true; } -#else -static bool __init hv_init_tsc_clocksource(void) -{ - return false; -} -#endif - void __init hv_init_clocksource(void) { diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig index 9a59957922d4..79e5356a737a 100644 --- a/drivers/hv/Kconfig +++ b/drivers/hv/Kconfig @@ -14,9 +14,6 @@ config HYPERV 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 diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h index a821deb8ecb2..f72e4619d0a7 100644 --- a/include/clocksource/hyperv_timer.h +++ b/include/clocksource/hyperv_timer.h @@ -28,12 +28,10 @@ extern void hv_stimer_cleanup(unsigned int cpu); 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 @@ -102,6 +100,6 @@ static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, { return U64_MAX; } -#endif /* CONFIG_HYPERV_TSCPAGE */ +#endif /* CONFIG_HYPERV_TIMER */ #endif -- 2.20.1