Parallel CPU bringup for x86_64
From: | Usama Arif <usama.arif-AT-bytedance.com> | |
To: | dwmw2-AT-infradead.org, tglx-AT-linutronix.de, kim.phillips-AT-amd.com | |
Subject: | [PATCH v8 0/9] Parallel CPU bringup for x86_64 | |
Date: | Thu, 09 Feb 2023 15:41:47 +0000 | |
Message-ID: | <20230209154156.266385-1-usama.arif@bytedance.com> | |
Cc: | arjan-AT-linux.intel.com, mingo-AT-redhat.com, bp-AT-alien8.de, dave.hansen-AT-linux.intel.com, hpa-AT-zytor.com, x86-AT-kernel.org, pbonzini-AT-redhat.com, paulmck-AT-kernel.org, linux-kernel-AT-vger.kernel.org, kvm-AT-vger.kernel.org, rcu-AT-vger.kernel.org, mimoja-AT-mimoja.de, hewenliang4-AT-huawei.com, thomas.lendacky-AT-amd.com, seanjc-AT-google.com, pmenzel-AT-molgen.mpg.de, fam.zheng-AT-bytedance.com, punit.agrawal-AT-bytedance.com, simon.evans-AT-bytedance.com, liangma-AT-liangbit.com, Usama Arif <usama.arif-AT-bytedance.com> | |
Archive-link: | Article |
The major change over v7 is fixing CPU0 hotplug not working as reported by Paul E. McKenney using rcu torture tests. This is fixed by setting up the initial_gs, initial_stack and early_gdt_descr properly for this case. The improvement in boot time is the same as v7. Thanks, Usama Changes across versions: v2: Cut it back to just INIT/SIPI/SIPI in parallel for now, nothing more v3: Clean up x2apic patch, add MTRR optimisation, lock topology update in preparation for more parallelisation. v4: Fixes to the real mode parallelisation patch spotted by SeanC, to avoid scribbling on initial_gs in common_cpu_up(), and to allow all 24 bits of the physical X2APIC ID to be used. That patch still needs a Signed-off-by from its original author, who once claimed not to remember writing it at all. But now we've fixed it, hopefully he'll admit it now :) v5: rebase to v6.1 and remeasure performance, disable parallel bringup for AMD CPUs. v6: rebase to v6.2-rc6, disabled parallel boot on amd as a cpu bug and reused timer calibration for secondary CPUs. v7: [David Woodhouse] iterate over all possible CPUs to find any existing cluster mask in alloc_clustermask. (patch 1/9) Keep parallel AMD support enabled in AMD, using APIC ID in CPUID leaf 0x0B (for x2APIC mode) or CPUID leaf 0x01 where 8 bits are sufficient. Included sanity checks for APIC id from 0x0B. (patch 6/9) Removed patch for reusing timer calibration for secondary CPUs. commit message and code improvements. v8: Fix CPU0 hotplug by setting up the initial_gs, initial_stack and early_gdt_descr. Drop trampoline lock and bail if APIC ID not found in find_cpunr. Code comments improved and debug prints added. David Woodhouse (9): x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() x86/smpboot: Split up native_cpu_up into separate phases and document them x86/smpboot: Support parallel startup of secondary CPUs x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup x86/smpboot: Serialize topology updates for secondary bringup arch/x86/include/asm/realmode.h | 3 + arch/x86/include/asm/smp.h | 14 +- arch/x86/include/asm/topology.h | 2 - arch/x86/kernel/acpi/sleep.c | 1 + arch/x86/kernel/apic/apic.c | 2 +- arch/x86/kernel/apic/x2apic_cluster.c | 130 ++++++---- arch/x86/kernel/cpu/common.c | 6 +- arch/x86/kernel/cpu/mtrr/mtrr.c | 9 + arch/x86/kernel/head_64.S | 99 +++++++- arch/x86/kernel/smpboot.c | 350 +++++++++++++++++++------- arch/x86/realmode/init.c | 3 + arch/x86/realmode/rm/trampoline_64.S | 14 ++ arch/x86/xen/smp_pv.c | 4 +- include/linux/cpuhotplug.h | 2 + include/linux/smpboot.h | 7 + kernel/cpu.c | 31 ++- kernel/smpboot.c | 2 +- kernel/smpboot.h | 2 - 18 files changed, 521 insertions(+), 160 deletions(-) -- 2.25.1