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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2020-08-18 19:19:17 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-03 15:01:11 +0100 |
| commit | b6254ced4da6cf28d49fbffe24ee4b3286dcb3f4 (patch) | |
| tree | b540b61c16700a38016b462239cef5ff6319de9a /arch/powerpc/include/asm/processor.h | |
| parent | powerpc/ptrace: Create ptrace_get_fpr() and ptrace_put_fpr() (diff) | |
| download | linux-b6254ced4da6cf28d49fbffe24ee4b3286dcb3f4.tar.xz linux-b6254ced4da6cf28d49fbffe24ee4b3286dcb3f4.zip | |
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/include/asm/processor.h')
| -rw-r--r-- | arch/powerpc/include/asm/processor.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 333e3b6c76fb..0792530bedef 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -164,8 +164,10 @@ struct thread_struct { #endif /* Debug Registers */ struct debug_reg debug; +#ifdef CONFIG_PPC_FPU_REGS struct thread_fp_state fp_state; struct thread_fp_state *fp_save_area; +#endif int fpexc_mode; /* floating-point exception mode */ unsigned int align_ctl; /* alignment handling control */ #ifdef CONFIG_HAVE_HW_BREAKPOINT |