Date: Sat, 1 Feb 2020 19:49:13 +0000 (UTC) From: Conrad Meyer <cem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357378 - in head/sys/x86: cpufreq include Message-ID: <202002011949.011JnDGE021647@repo.freebsd.org>
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Author: cem Date: Sat Feb 1 19:49:13 2020 New Revision: 357378 URL: https://svnweb.freebsd.org/changeset/base/357378 Log: hwpstate_intel(4): Add fallback EPP using PERF_BIAS MSR Per Intel SDM (Vol 3b Part 2), if HWP indicates EPP (energy-performance preference) is not supported, the hardware instead uses the ENERGY_PERF_BIAS MSR. In the epp sysctl handler, fall back to that MSR if HWP does not support EPP and CPUID indicates the ENERGY_PERF_BIAS MSR is supported. Modified: head/sys/x86/cpufreq/hwpstate_intel.c head/sys/x86/include/specialreg.h Modified: head/sys/x86/cpufreq/hwpstate_intel.c ============================================================================== --- head/sys/x86/cpufreq/hwpstate_intel.c Sat Feb 1 19:46:02 2020 (r357377) +++ head/sys/x86/cpufreq/hwpstate_intel.c Sat Feb 1 19:49:13 2020 (r357378) @@ -88,6 +88,7 @@ struct hwp_softc { bool hwp_activity_window; bool hwp_pref_ctrl; bool hwp_pkg_ctrl; + bool hwp_perf_bias; uint64_t req; /* Cached copy of last request */ @@ -215,6 +216,26 @@ raw_to_percent(int x) return (round10(x * 1000 / 0xff)); } +/* Range of MSR_IA32_ENERGY_PERF_BIAS is more limited: 0-0xf. */ +static inline int +percent_to_raw_perf_bias(int x) +{ + /* + * Round up so that raw values present as nice round human numbers and + * also round-trip to the same raw value. + */ + MPASS(x <= 100 && x >= 0); + return (((0xf * x) + 50) / 100); +} + +static inline int +raw_to_percent_perf_bias(int x) +{ + /* Rounding to nice human numbers despite a step interval of 6.67%. */ + MPASS(x <= 0xf && x >= 0); + return (((x * 20) / 0xf) * 5); +} + static int sysctl_epp_select(SYSCTL_HANDLER_ARGS) { @@ -227,7 +248,7 @@ sysctl_epp_select(SYSCTL_HANDLER_ARGS) dev = oidp->oid_arg1; sc = device_get_softc(dev); - if (!sc->hwp_pref_ctrl) + if (!sc->hwp_pref_ctrl && !sc->hwp_perf_bias) return (ENODEV); pc = cpu_get_pcpu(dev); @@ -238,11 +259,24 @@ sysctl_epp_select(SYSCTL_HANDLER_ARGS) sched_bind(curthread, pc->pc_cpuid); thread_unlock(curthread); - ret = rdmsr_safe(MSR_IA32_HWP_REQUEST, &requested); - if (ret) - goto out; - val = (requested & IA32_HWP_REQUEST_ENERGY_PERFORMANCE_PREFERENCE) >> 24; - val = raw_to_percent(val); + if (sc->hwp_pref_ctrl) { + ret = rdmsr_safe(MSR_IA32_HWP_REQUEST, &requested); + if (ret) + goto out; + val = (requested & IA32_HWP_REQUEST_ENERGY_PERFORMANCE_PREFERENCE) >> 24; + val = raw_to_percent(val); + } else { + /* + * If cpuid indicates EPP is not supported, the HWP controller + * uses MSR_IA32_ENERGY_PERF_BIAS instead (Intel SDM ยง14.4.4). + * This register is per-core (but not HT). + */ + ret = rdmsr_safe(MSR_IA32_ENERGY_PERF_BIAS, &requested); + if (ret) + goto out; + val = requested & IA32_ENERGY_PERF_BIAS_POLICY_HINT_MASK; + val = raw_to_percent_perf_bias(val); + } MPASS(val >= 0 && val <= 100); @@ -255,12 +289,18 @@ sysctl_epp_select(SYSCTL_HANDLER_ARGS) goto out; } - val = percent_to_raw(val); + if (sc->hwp_pref_ctrl) { + val = percent_to_raw(val); - requested &= ~IA32_HWP_REQUEST_ENERGY_PERFORMANCE_PREFERENCE; - requested |= val << 24; + requested &= ~IA32_HWP_REQUEST_ENERGY_PERFORMANCE_PREFERENCE; + requested |= val << 24; - ret = wrmsr_safe(MSR_IA32_HWP_REQUEST, requested); + ret = wrmsr_safe(MSR_IA32_HWP_REQUEST, requested); + } else { + requested = percent_to_raw_perf_bias(val); + MPASS((requested & ~IA32_ENERGY_PERF_BIAS_POLICY_HINT_MASK) == 0); + ret = wrmsr_safe(MSR_IA32_ENERGY_PERF_BIAS, requested); + } out: thread_lock(curthread); @@ -405,6 +445,7 @@ intel_hwpstate_attach(device_t dev) sc = device_get_softc(dev); sc->dev = dev; + /* eax */ if (cpu_power_eax & CPUTPM1_HWP_NOTIFICATION) sc->hwp_notifications = true; if (cpu_power_eax & CPUTPM1_HWP_ACTIVITY_WINDOW) @@ -413,6 +454,10 @@ intel_hwpstate_attach(device_t dev) sc->hwp_pref_ctrl = true; if (cpu_power_eax & CPUTPM1_HWP_PKG) sc->hwp_pkg_ctrl = true; + + /* ecx */ + if (cpu_power_ecx & CPUID_PERF_BIAS) + sc->hwp_perf_bias = true; ret = set_autonomous_hwp(sc); if (ret) Modified: head/sys/x86/include/specialreg.h ============================================================================== --- head/sys/x86/include/specialreg.h Sat Feb 1 19:46:02 2020 (r357377) +++ head/sys/x86/include/specialreg.h Sat Feb 1 19:49:13 2020 (r357378) @@ -812,6 +812,9 @@ #define IA32_HWP_REQUEST_MAXIMUM_PERFORMANCE (0xffULL << 8) #define IA32_HWP_MINIMUM_PERFORMANCE (0xffULL << 0) +/* MSR IA32_ENERGY_PERF_BIAS */ +#define IA32_ENERGY_PERF_BIAS_POLICY_HINT_MASK (0xfULL << 0) + /* * PAT modes. */
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