Re: [PATCH v3 next 06/10] lib: test_mul_u64_u64_div_u64: Test both generic and arch versions

[Nicolas Pitre]

On Sat, 14 Jun 2025, Nicolas Pitre wrote:

> On Sat, 14 Jun 2025, David Laight wrote:
> 
> > Change the #if in div64.c so that test_mul_u64_u64_div_u64.c
> > can compile and test the generic version (including the 'long multiply')
> > on architectures (eg amd64) that define their own copy.
> > Test the kernel version and the locally compiled version on all arch.
> > Output the time taken (in ns) on the 'test completed' trace.
> > 
> > For reference, on my zen 5, the optimised version takes ~220ns and the
> > generic version ~3350ns.
> > Using the native multiply saves ~200ns and adding back the ilog2() 'optimisation'
> > test adds ~50ms.
> > 
> > Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>
> 
> Reviewed-by: Nicolas Pitre <npitre@xxxxxxxxxxxx>

In fact this doesn't compile on ARM32. The following is needed to fix that:

commit 271a7224634699721b6383ba28f37b23f901319e
Author: Nicolas Pitre <nico@xxxxxxxxxxx>
Date:   Tue Jun 17 17:14:05 2025 -0400

    fixup! lib: test_mul_u64_u64_div_u64: Test both generic and arch versions

diff --git a/lib/math/test_mul_u64_u64_div_u64.c b/lib/math/test_mul_u64_u64_div_u64.c
index 88316e68512c..44df9aa39406 100644
--- a/lib/math/test_mul_u64_u64_div_u64.c
+++ b/lib/math/test_mul_u64_u64_div_u64.c
@@ -153,7 +153,10 @@ static void __exit test_exit(void)
 }
 
 /* Compile the generic mul_u64_add_u64_div_u64() code */
+#define __div64_32 __div64_32
+#define div_s64_rem div_s64_rem
 #define div64_u64 div64_u64
+#define div64_u64_rem div64_u64_rem
 #define div64_s64 div64_s64
 #define iter_div_u64_rem iter_div_u64_rem