Messages in this thread | | | Subject | Re: [PATCH] tools/testing/selftests/powerpc: Add Anton's null_syscall benchmark to the selftests | From | Christophe Leroy <> | Date | Wed, 23 Jan 2019 15:56:06 +0100 |
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Le 27/09/2016 à 16:10, Rui Teng a écrit : > From: Anton Blanchard <anton@au.ibm.com> > > Pull in a version of Anton's null_syscall benchmark: > http://ozlabs.org/~anton/junkcode/null_syscall.c > Into tools/testing/selftests/powerpc/benchmarks. > > Suggested-by: Michael Ellerman <mpe@ellerman.id.au> > Signed-off-by: Anton Blanchard <anton@au.ibm.com> > Signed-off-by: Rui Teng <rui.teng@linux.vnet.ibm.com> > --- > .../testing/selftests/powerpc/benchmarks/Makefile | 2 +- > .../selftests/powerpc/benchmarks/null_syscall.c | 157 +++++++++++++++++++++ > 2 files changed, 158 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/powerpc/benchmarks/null_syscall.c >
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> + > +static void do_null_syscall(unsigned long nr) > +{ > + unsigned long i; > + > + for (i = 0; i < nr; i++) > + getppid(); > +} > +
Looks like getppid() performs a rcu_read_lock(). Is that what we want ?
Shouldn't we use getpid() instead for a lighter syscall ?
Christophe
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