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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/kernel/asm-offsets.c | |
| 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/kernel/asm-offsets.c')
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index a2dcb8ed79b9..81d68494d026 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -110,9 +110,11 @@ int main(void) #ifdef CONFIG_BOOKE OFFSET(THREAD_NORMSAVES, thread_struct, normsave[0]); #endif +#ifdef CONFIG_PPC_FPU OFFSET(THREAD_FPEXC_MODE, thread_struct, fpexc_mode); OFFSET(THREAD_FPSTATE, thread_struct, fp_state.fpr); OFFSET(THREAD_FPSAVEAREA, thread_struct, fp_save_area); +#endif OFFSET(FPSTATE_FPSCR, thread_fp_state, fpscr); OFFSET(THREAD_LOAD_FP, thread_struct, load_fp); #ifdef CONFIG_ALTIVEC |