diff options
| author | Shrikanth Hegde <sshegde@linux.ibm.com> | 2025-02-11 00:13:34 +0530 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2025-04-16 22:30:22 +0530 |
| commit | 6ad7751537e884c45b5340a4a24c25535f0d9c13 (patch) | |
| tree | 47f78f2c38487d65e69a0e2cc19180840c1a24c4 /arch/powerpc/include/asm/preempt.h | |
| parent | 28affd477bf53ddd89b16e4dd7bacf64a1eaf116 (diff) | |
powerpc: enable dynamic preemption
Once the lazy preemption is supported, it would be desirable to change
the preemption models at runtime. So add support for dynamic preemption
using DYNAMIC_KEY.
::Tested lightly on Power10 LPAR
Performance numbers indicate that, preempt=none(no dynamic) and
preempt=none(dynamic) are close.
cat /sys/kernel/debug/sched/preempt
(none) voluntary full lazy
perf stat -e probe:__cond_resched -a sleep 1
Performance counter stats for 'system wide':
1,253 probe:__cond_resched
echo full > /sys/kernel/debug/sched/preempt
cat /sys/kernel/debug/sched/preempt
none voluntary (full) lazy
perf stat -e probe:__cond_resched -a sleep 1
Performance counter stats for 'system wide':
0 probe:__cond_resched
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250210184334.567383-2-sshegde@linux.ibm.com
Diffstat (limited to 'arch/powerpc/include/asm/preempt.h')
| -rw-r--r-- | arch/powerpc/include/asm/preempt.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/preempt.h b/arch/powerpc/include/asm/preempt.h new file mode 100644 index 000000000000..000e2b9681f3 --- /dev/null +++ b/arch/powerpc/include/asm/preempt.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_POWERPC_PREEMPT_H +#define __ASM_POWERPC_PREEMPT_H + +#include <asm-generic/preempt.h> + +#if defined(CONFIG_PREEMPT_DYNAMIC) +#include <linux/jump_label.h> +DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched); +#define need_irq_preemption() \ + (static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched)) +#else +#define need_irq_preemption() (IS_ENABLED(CONFIG_PREEMPTION)) +#endif + +#endif /* __ASM_POWERPC_PREEMPT_H */ |