Re: [PATCH V2 3/3] scsi: mptxsas: offload IRQ execution

From: Hannes Reinecke <hare@suse.de>
To: Sinan Kaya <okaya@codeaurora.org>,
	linux-scsi@vger.kernel.org, timur@codeaurora.org,
	cov@codeaurora.org, jcm@redhat.com
Cc: agross@codeaurora.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Nagalakshmi Nandigama <nagalakshmi.nandigama@avagotech.com>,
	Praveen Krishnamoorthy <praveen.krishnamoorthy@avagotech.com>,
	Sreekanth Reddy <sreekanth.reddy@avagotech.com>,
	Abhijit Mahajan <abhijit.mahajan@avagotech.com>,
	"James E.J. Bottomley" <JBottomley@odin.com>,
	MPT-FusionLinux.pdl@avagotech.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 3/3] scsi: mptxsas: offload IRQ execution
Date: Mon, 09 Nov 2015 08:15:40 +0100	[thread overview]
Message-ID: <5640481C.9000505@suse.de> (raw)
In-Reply-To: <1447034266-28003-4-git-send-email-okaya@codeaurora.org>

On 11/09/2015 02:57 AM, Sinan Kaya wrote:
> The mpt2sas and mpt3sas drivers are spinning forever in
> their IRQ handlers if there are a lot of jobs queued up
> by the PCIe card. This handler is causing spikes for
> the rest of the system and sluggish behavior.
> 
> Marking all MSI interrupts as non-shared and moving the
> MSI interrupts to thread context. This relexes the rest
> of the system execution.
> 
NACK.

If there is a scalability issue when handling interrupts
it should be fixed in the driver directly.

Looking at the driver is should be possible to implement
a worker thread handling the reply descriptor, and having the
interrupt only to fetch the reply descriptor.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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