e5ba90abb2
Similar with x86, when VM is detected, revert to a simple test-and-set
lock to avoid the horrors of queue preemption.
Tested on 3C5000 Dual-way machine with 32 cores and 2 numa nodes,
test case is kcbench on kernel mainline 6.10, the detailed command is
"kcbench --src /root/src/linux"
Performance on host machine
kernel compile time performance impact
Original 150.29 seconds
With patch 150.19 seconds almost no impact
Performance on virtual machine:
1. 1 VM with 32 vCPUs and 2 numa node, numa node pinned
kernel compile time performance impact
Original 170.87 seconds
With patch 171.73 seconds almost no impact
2. 2 VMs, each VM with 32 vCPUs and 2 numa node, numa node pinned
kernel compile time performance impact
Original 2362.04 seconds
With patch 354.73 seconds +565%
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
43 lines
773 B
C
43 lines
773 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_LOONGARCH_PARAVIRT_H
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#define _ASM_LOONGARCH_PARAVIRT_H
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#ifdef CONFIG_PARAVIRT
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#include <linux/static_call_types.h>
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struct static_key;
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extern struct static_key paravirt_steal_enabled;
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extern struct static_key paravirt_steal_rq_enabled;
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u64 dummy_steal_clock(int cpu);
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DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
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static inline u64 paravirt_steal_clock(int cpu)
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{
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return static_call(pv_steal_clock)(cpu);
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}
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int __init pv_ipi_init(void);
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int __init pv_time_init(void);
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int __init pv_spinlock_init(void);
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#else
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static inline int pv_ipi_init(void)
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{
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return 0;
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}
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static inline int pv_time_init(void)
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{
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return 0;
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}
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static inline int pv_spinlock_init(void)
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{
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return 0;
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}
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#endif // CONFIG_PARAVIRT
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#endif
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