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From: Marc Zyngier <marc.zyngier@arm.com>
To: Julien Thierry <julien.thierry@arm.com>,
	linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, daniel.thompson@linaro.org,
	joel@joelfernandes.org, mark.rutland@arm.com,
	christoffer.dall@arm.com, james.morse@arm.com,
	catalin.marinas@arm.com, will.deacon@arm.com,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>
Subject: Re: [PATCH v5 19/27] irqchip/gic-v3: Remove acknowledge loop
Date: Wed, 3 Oct 2018 10:26:00 +0100	[thread overview]
Message-ID: <ee78b536-6a87-52c7-16c4-292f7ecbe61a@arm.com> (raw)
In-Reply-To: <1535471497-38854-20-git-send-email-julien.thierry@arm.com>

On 28/08/18 16:51, Julien Thierry wrote:
> Multiple interrupts pending for a CPU is actually rare. Doing an
> acknowledge loop does not give much better performance or even can
> deteriorate them.
> 
> Do not loop when an interrupt has been acknowledged, just return
> from interrupt and wait for another one to be raised.
> 
> Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> ---
>   drivers/irqchip/irq-gic-v3.c | 65 +++++++++++++++++++++-----------------------
>   1 file changed, 31 insertions(+), 34 deletions(-)

It would probably be valuable to do the same thing for GICv1/v2, where 
the MMIO access can be even more costly.

In the meantime, I've queued this for 4.20.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2018-10-03  9:26 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-28 15:51 [PATCH v5 00/27] arm64: provide pseudo NMI with GICv3 Julien Thierry
2018-08-28 15:51 ` [PATCH v5 01/27] arm64: cpufeature: Set SYSREG_GIC_CPUIF as a boot system feature Julien Thierry
2018-09-21 15:56   ` Marc Zyngier
     [not found]     ` <MWHPR0601MB3707D7CF3B55BF40EEEA0D52C4160@MWHPR0601MB3707.namprd06.prod.outlook.com>
2018-09-25  8:13       ` Marc Zyngier
2018-08-28 15:51 ` [PATCH v5 02/27] arm64: cpufeature: Use alternatives for VHE cpu_enable Julien Thierry
2018-09-12 10:28   ` James Morse
2018-09-12 12:03     ` Julien Thierry
2018-09-18 17:46       ` James Morse
2018-09-12 12:37     ` Suzuki K Poulose
2018-08-28 15:51 ` [PATCH v5 03/27] arm64: alternative: Apply alternatives early in boot process Julien Thierry
2018-09-12 10:29   ` James Morse
2018-09-12 16:49     ` Julien Thierry
2018-09-17 23:44       ` Daniel Thompson
2018-09-18  7:37         ` Julien Thierry
2018-09-18 17:47         ` James Morse
2018-09-21 16:05       ` Marc Zyngier
2018-08-28 15:51 ` [PATCH v5 04/27] arm64: daifflags: Use irqflags functions for daifflags Julien Thierry
2018-09-12 12:28   ` James Morse
2018-10-03 15:09   ` Catalin Marinas
2018-08-28 15:51 ` [PATCH v5 05/27] arm64: Use daifflag_restore after bp_hardening Julien Thierry
2018-09-12 10:32   ` James Morse
2018-09-12 11:11     ` Julien Thierry
2018-09-12 12:28       ` James Morse
2018-09-12 13:03         ` Julien Thierry
2018-10-03 15:12   ` Catalin Marinas
2018-08-28 15:51 ` [PATCH v5 06/27] arm64: Delay daif masking for user return Julien Thierry
2018-09-12 10:31   ` James Morse
2018-09-12 13:07     ` Julien Thierry
2018-08-28 15:51 ` [PATCH v5 07/27] arm64: xen: Use existing helper to check interrupt status Julien Thierry
2018-08-29 21:35   ` Stefano Stabellini
2018-10-03 15:14   ` Catalin Marinas
2018-08-28 15:51 ` [PATCH v5 08/27] irqchip/gic: Unify GIC priority definitions Julien Thierry
2018-10-03  9:24   ` Marc Zyngier
2018-08-28 15:51 ` [PATCH v5 09/27] irqchip/gic: Lower priority of GIC interrupts Julien Thierry
2018-08-28 15:51 ` [PATCH v5 10/27] arm64: cpufeature: Add cpufeature for IRQ priority masking Julien Thierry
2018-08-28 15:51 ` [PATCH v5 11/27] arm64: Make PMR part of task context Julien Thierry
2018-08-28 15:51 ` [PATCH v5 12/27] arm64: Unmask PMR before going idle Julien Thierry
2018-08-28 15:51 ` [PATCH v5 13/27] arm/arm64: gic-v3: Add helper functions to manage IRQ priorities Julien Thierry
2018-08-28 15:51 ` [PATCH v5 14/27] arm64: kvm: Unmask PMR before entering guest Julien Thierry
2018-08-28 15:51 ` [PATCH v5 15/27] arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking Julien Thierry
2018-09-21 17:39   ` Julien Thierry
2018-09-21 17:55     ` Julien Thierry
2018-08-28 15:51 ` [PATCH v5 16/27] arm64: daifflags: Include PMR in daifflags restore operations Julien Thierry
2018-08-28 15:51 ` [PATCH v5 17/27] irqchip/gic-v3: Factor group0 detection into functions Julien Thierry
2018-08-28 15:51 ` [PATCH v5 18/27] irqchip/gic-v3: Do not overwrite PMR value Julien Thierry
2018-08-28 15:51 ` [PATCH v5 19/27] irqchip/gic-v3: Remove acknowledge loop Julien Thierry
2018-10-03  9:26   ` Marc Zyngier [this message]
2018-08-28 15:51 ` [PATCH v5 20/27] irqchip/gic-v3: Switch to PMR masking after IRQ acknowledge Julien Thierry
2018-08-28 15:51 ` [PATCH v5 21/27] arm64: Switch to PMR masking when starting CPUs Julien Thierry
2018-08-28 15:51 ` [PATCH v5 22/27] arm64: Add build option for IRQ masking via priority Julien Thierry
2018-08-28 15:51 ` [PATCH v5 23/27] arm64: Handle serror in NMI context Julien Thierry
2018-08-28 15:51 ` [PATCH v5 24/27] irqchip/gic-v3: Detect current view of GIC priorities Julien Thierry
2018-08-28 15:51 ` [PATCH v5 25/27] irqchip/gic-v3: Add base support for pseudo-NMI Julien Thierry
2018-08-28 15:51 ` [PATCH v5 26/27] irqchip/gic: Add functions to access irq priorities Julien Thierry
2018-08-28 15:51 ` [PATCH v5 27/27] irqchip/gic-v3: Allow interrupts to be set as pseudo-NMI Julien Thierry
2018-08-29 11:37 ` [PATCH v5 00/27] arm64: provide pseudo NMI with GICv3 Daniel Thompson
2018-08-29 12:58   ` Julien Thierry

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