Re: [WIP PATCHSET 0/4] WIP branch for bfq-mq

[Paolo Valente]

> Il giorno 10 feb 2017, alle ore 19:13, Bart Van Assche <bart.vanassche@xxxxxxxxxxx> ha scritto:
> 
> On 02/10/2017 08:49 AM, Paolo Valente wrote:
>>> $ grep '^C.*_MQ_' .config
>>> CONFIG_BLK_MQ_PCI=y
>>> CONFIG_MQ_IOSCHED_BFQ=y
>>> CONFIG_MQ_IOSCHED_DEADLINE=y
>>> CONFIG_MQ_IOSCHED_NONE=y
>>> CONFIG_DEFAULT_MQ_BFQ_MQ=y
>>> CONFIG_DEFAULT_MQ_IOSCHED="bfq-mq"
>>> CONFIG_SCSI_MQ_DEFAULT=y
>>> CONFIG_DM_MQ_DEFAULT=y
>>> 
>> 
>> Could you reconfigure with none or mq-deadline as default, check
>> whether the system boots, and, it it does, switch manually to bfq-mq,
>> check what happens, and, in the likely case of a failure, try to get
>> the oops?
> 
> Hello Paolo,
> 
> I just finished performing that test with the following kernel config:
> $ grep '^C.*_MQ_' .config
> CONFIG_BLK_MQ_PCI=y
> CONFIG_MQ_IOSCHED_BFQ=y
> CONFIG_MQ_IOSCHED_DEADLINE=y
> CONFIG_MQ_IOSCHED_NONE=y
> CONFIG_DEFAULT_MQ_DEADLINE=y
> CONFIG_DEFAULT_MQ_IOSCHED="mq-deadline"
> CONFIG_SCSI_MQ_DEFAULT=y
> CONFIG_DM_MQ_DEFAULT=y
> 
> After the system came up I logged in, switched to the bfq-mq scheduler
> and ran several I/O tests against the boot disk.

Without any failure, right?

Unfortunately, as you can imagine, no boot failure occurred on
any of my test systems so far :(

This version of bfq-mq can be configured to print all its activity in
the kernel log, by just defining a macro.  This will of course slow
down the system so much to make it probably unusable, if bfq-mq is
active from boot.  Yet, the failure may still occur so early to make
this approach useful to discover where bfq-mq gets stuck.  As of now I
have no better ideas.  Any suggestion is welcome.

Thanks,
Paolo

> Sorry but nothing
> interesting appeared in the kernel log.
> 
> Bart.
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