[PATCH] powerpc: use IRQF_NO_DEBUG for IPIs

There is no need to use the lockup detector ("noirqdebug") for IPIs.
The ipistorm benchmark measures a ~10% improvement on high systems
when this flag is set.

Cc: Thomas Gleixner <redacted>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 arch/powerpc/sysdev/xics/xics-common.c | 2 +-
 arch/powerpc/sysdev/xive/common.c      | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index b14c502e56a8..18174ccefbc0 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c

@@ -133,7 +133,7 @@ static void xics_request_ipi(void)
 	 * IPIs are marked IRQF_PERCPU. The handler was set in map.
 	 */
 	BUG_ON(request_irq(ipi, icp_ops->ipi_action,
-			   IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
+			   IRQF_NO_DEBUG | IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
 }
 
 void __init xics_smp_probe(void)

diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index dbdbbc2f1dc5..9ab44d069704 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c

@@ -1161,7 +1161,8 @@ static int __init xive_request_ipi(void)
 		snprintf(xid->name, sizeof(xid->name), "IPI-%d", node);
 
 		ret = request_irq(xid->irq, xive_muxed_ipi_action,
-				  IRQF_PERCPU | IRQF_NO_THREAD, xid->name, NULL);
+				  IRQF_NO_DEBUG | IRQF_PERCPU | IRQF_NO_THREAD,
+				  xid->name, NULL);
 
 		WARN(ret < 0, "Failed to request IPI %d: %d\n", xid->irq, ret);
 	}

-- 
2.31.1

On Mon, Jul 19 2021 at 15:06, Cédric Le Goater wrote:

There is no need to use the lockup detector ("noirqdebug") for IPIs.
The ipistorm benchmark measures a ~10% improvement on high systems
when this flag is set.

Cc: Thomas Gleixner <redacted>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

Reviewed-by: Thomas Gleixner <redacted>

On Mon, 19 Jul 2021 15:06:14 +0200, Cédric Le Goater wrote:

There is no need to use the lockup detector ("noirqdebug") for IPIs.
The ipistorm benchmark measures a ~10% improvement on high systems
when this flag is set.

Applied to powerpc/next.

[1/1] powerpc: use IRQF_NO_DEBUG for IPIs
      https://git.kernel.org/powerpc/c/17df41fec5b80b16ea4774495f1eb730e2225619

cheers