Call cond_resched() to let the scheduler reschedule the
CPU at the end of each test pass.

If the kernel is configured with CONFIG_PREEMPT_NONE=y (or
preempt=none is used on the kernel command line), the only
time the scheduler will intervene is when cond_resched()
is called. So, repeated calls to
	modprobe tcrypt mode=<something>

hold the CPU for a long time.

Signed-off-by: Robert Elliott <elliott@hpe.com>
---
 crypto/tcrypt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
index 3e9e4adeef02..916bddbf4e75 100644
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -3027,6 +3027,7 @@ static int do_test(const char *alg, u32 type, u32 mask, int m, u32 num_mb)
 
 	}
 
+	cond_resched();
 	return ret;
 }
 
-- 
2.38.1

On Mon, Dec 19, 2022 at 02:37:33PM -0600, Robert Elliott wrote:
> Call cond_resched() to let the scheduler reschedule the
> CPU at the end of each test pass.
> 
> If the kernel is configured with CONFIG_PREEMPT_NONE=y (or
> preempt=none is used on the kernel command line), the only
> time the scheduler will intervene is when cond_resched()
> is called. So, repeated calls to
> 	modprobe tcrypt mode=<something>
> 
> hold the CPU for a long time.
> 
> Signed-off-by: Robert Elliott <elliott@hpe.com>
> ---
>  crypto/tcrypt.c | 1 +
>  1 file changed, 1 insertion(+)

I don't really see the point of this.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt