| From: |
| Usama Arif <usama.arif-AT-bytedance.com> |
| To: |
| dwmw2-AT-infradead.org, tglx-AT-linutronix.de |
| Subject: |
| [PATCH 0/9] Parallel CPU bringup for x86_64 |
| Date: |
| Wed, 01 Feb 2023 20:43:29 +0000 |
| Message-ID: |
| <20230201204338.1337562-1-usama.arif@bytedance.com> |
| Cc: |
| 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 |
This patchseries is from the work done by David Woodhouse (v4: https://lore.kernel.org/all/20220201205328.123066-1-dwmw2...).
The parallel CPU bringup is disabled for all AMD CPUs in this version: (see discussions: https://lore.kernel.org/all/bc3f2b1332c4bb77558df8aa36493... and
https://lore.kernel.org/all/3b6ac86fdc800cac5806433daf14a...).
Doing INIT/SIPI/SIPI in parallel brings down the time for smpboot from ~700ms
to 100ms (85% improvement) on a server with 128 CPUs split across 2 NUMA
nodes.
Adding another cpuhp state for do_wait_cpu_initialized to make sure cpu_init
is reached in parallel as proposed by David in v1 will bring it down further
to ~30ms. Making this change would be dependent on this patchseries, so they
could be explored if this gets merged.
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.
David Woodhouse (8):
x86/apic/x2apic: Fix parallel handling of cluster_mask
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: 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
Thomas Gleixner (1):
x86/smpboot: Support parallel startup of secondary CPUs
arch/x86/include/asm/realmode.h | 3 +
arch/x86/include/asm/smp.h | 13 +-
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 | 108 +++++----
arch/x86/kernel/cpu/common.c | 6 +-
arch/x86/kernel/cpu/mtrr/mtrr.c | 9 +
arch/x86/kernel/head_64.S | 73 ++++++
arch/x86/kernel/smpboot.c | 324 ++++++++++++++++++--------
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 | 27 ++-
kernel/smpboot.c | 2 +-
kernel/smpboot.h | 2 -
18 files changed, 443 insertions(+), 159 deletions(-)
--
2.25.1
