diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2020-08-18 17:19:17 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-04 01:01:11 +1100 |
| commit | b6254ced4da6cf28d49fbffe24ee4b3286dcb3f4 (patch) | |
| tree | b540b61c16700a38016b462239cef5ff6319de9a /arch/powerpc/kernel/signal.h | |
| parent | 4d90eb97e292c7b14de8ba59fded35b340c73101 (diff) | |
powerpc/signal: Don't manage floating point regs when no FPU
There is no point in copying floating point regs when there
is no FPU and MATH_EMULATION is not selected.
Create a new CONFIG_PPC_FPU_REGS bool that is selected by
CONFIG_MATH_EMULATION and CONFIG_PPC_FPU, and use it to
opt out everything related to fp_state in thread_struct.
The asm const used only by fpu.S are opted out with CONFIG_PPC_FPU
as fpu.S build is conditionnal to CONFIG_PPC_FPU.
The following app spends approx 8.1 seconds system time on an 8xx
without the patch, and 7.0 seconds with the patch (13.5% reduction).
On an 832x, it spends approx 2.6 seconds system time without
the patch and 2.1 seconds with the patch (19% reduction).
void sigusr1(int sig) { }
int main(int argc, char **argv)
{
int i = 100000;
signal(SIGUSR1, sigusr1);
for (;i--;)
raise(SIGUSR1);
exit(0);
}
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7569070083e6cd5b279bb5023da601aba3c06f3c.1597770847.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/kernel/signal.h')
| -rw-r--r-- | arch/powerpc/kernel/signal.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h index 4626d39cc0f0..6c2a33ab042c 100644 --- a/arch/powerpc/kernel/signal.h +++ b/arch/powerpc/kernel/signal.h @@ -34,7 +34,7 @@ unsigned long copy_fpr_to_user(void __user *to, struct task_struct *task); unsigned long copy_ckfpr_to_user(void __user *to, struct task_struct *task); unsigned long copy_fpr_from_user(struct task_struct *task, void __user *from); unsigned long copy_ckfpr_from_user(struct task_struct *task, void __user *from); -#else +#elif defined(CONFIG_PPC_FPU_REGS) static inline unsigned long copy_fpr_to_user(void __user *to, struct task_struct *task) { @@ -63,6 +63,18 @@ copy_ckfpr_from_user(struct task_struct *task, void __user *from) ELF_NFPREG * sizeof(double)); } #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ +#else +static inline unsigned long +copy_fpr_to_user(void __user *to, struct task_struct *task) +{ + return 0; +} + +static inline unsigned long +copy_fpr_from_user(struct task_struct *task, void __user *from) +{ + return 0; +} #endif #ifdef CONFIG_PPC64 |