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/traps.c | |
| 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/traps.c')
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 5006dcbe1d9f..5b39baa61590 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1190,7 +1190,9 @@ static void parse_fpe(struct pt_regs *regs) flush_fp_to_thread(current); +#ifdef CONFIG_PPC_FPU_REGS code = __parse_fpscr(current->thread.fp_state.fpscr); +#endif _exception(SIGFPE, regs, code, regs->nip); } |