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

From: Christopher Covington
Date: Wed Mar 16 2016 - 11:31:17 EST

On 11/10/2015 12:59 AM, Sinan Kaya wrote:
> On 11/9/2015 2:15 AM, Hannes Reinecke wrote:
>> 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.
> Can you go into the detail about which part of the _base_interrupt
> function needs to be executed in ISR context and which part can be
> queued up to worker thread?
> I'm not familiar with the hardware or the code. That's why, I moved the
> entire ISR into the thread context.

Hannes or others, any suggestions?

Christopher Covington

Qualcomm Innovation Center, Inc.
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