Re: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices

[Martin K. Petersen]

Long,

> If num_cpus=1, we don't have any sub channels.
>
> The host offers one sub channel for VM with 5 CPUs, after that it offers
> an additional sub channel every 4 CPUs.
>
> The primary channel is always offered.

Applied to 4.17/scsi-fixes. Thanks!

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Martin K. Petersen  Oracle Linux Engineering
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RE: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices

[Long Li]

> Subject: Re: [PATCH v2] storvsc: Set up correct queue depth values for IDE
> devices
> 
> 
> Long,
> 
> > Can you take a look at the following patch?
> 
> >> > + max_sub_channels =
> >> > +(num_cpus - 1) / storvsc_vcpus_per_sub_channel;
> 
> What happens if num_cpus = 1?

If num_cpus=1, we don't have any sub channels.

The host offers one sub channel for VM with 5 CPUs, after that it offers an 
additional sub channel every 4 CPUs.

The primary channel is always offered.

> 
> --
> Martin K. PetersenOracle Linux Engineering
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Re: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices

[Martin K. Petersen]

Long,

> Can you take a look at the following patch?

>> > + max_sub_channels =
>> > +  (num_cpus - 1) / storvsc_vcpus_per_sub_channel;

What happens if num_cpus = 1?

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Martin K. Petersen  Oracle Linux Engineering
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RE: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices

[Long Li]

Hi Martin

Can you take a look at the following patch?

Long

 
> > -Original Message-
> > From: linux-kernel-ow...@vger.kernel.org
> >  On Behalf Of Long Li
> > Sent: Thursday, March 22, 2018 2:47 PM
> > To: KY Srinivasan ; Haiyang Zhang
> > ; Stephen Hemminger
> ;
> > James E . J . Bottomley ; Martin K . Petersen
> > ; de...@linuxdriverproject.org; linux-
> > s...@vger.kernel.org; linux-ker...@vger.kernel.org
> > Cc: Long Li 
> > Subject: [PATCH v2] storvsc: Set up correct queue depth values for IDE
> > devices
> >
> > From: Long Li 
> >
> > Unlike SCSI and FC, we don't use multiple channels for IDE.
> > Also fix the calculation for sub-channels.
> >
> > Change log:
> > v2: Addressed comment on incorrect number of sub-channels.
> > (Michael Kelley )
> >
> > Signed-off-by: Long Li 
> 
> Reviewed-by: Michael Kelley 
> 
> > ---
> >  drivers/scsi/storvsc_drv.c | 7 +--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> > index 8c51d628b52e..a2ec0bc9e9fa 100644
> > --- a/drivers/scsi/storvsc_drv.c
> > +++ b/drivers/scsi/storvsc_drv.c
> > @@ -1722,11 +1722,14 @@ static int storvsc_probe(struct hv_device
> *device,
> > max_targets = STORVSC_MAX_TARGETS;
> > max_channels = STORVSC_MAX_CHANNELS;
> > /*
> > -* On Windows8 and above, we support sub-channels for
> storage.
> > +* On Windows8 and above, we support sub-channels for
> storage
> > +* on SCSI and FC controllers.
> >  * The number of sub-channels offerred is based on the
> number of
> >  * VCPUs in the guest.
> >  */
> > -   max_sub_channels = (num_cpus /
> storvsc_vcpus_per_sub_channel);
> > +   if (!dev_is_ide)
> > +   max_sub_channels =
> > +   (num_cpus - 1) /
> storvsc_vcpus_per_sub_channel;
> > }
> >
> > scsi_driver.can_queue = (max_outstanding_req_per_channel *
> > --
> > 2.14.1

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RE: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices

[Michael Kelley (EOSG)]

> -Original Message-
> From: linux-kernel-ow...@vger.kernel.org  
> On Behalf
> Of Long Li
> Sent: Thursday, March 22, 2018 2:47 PM
> To: KY Srinivasan ; Haiyang Zhang 
> ; Stephen
> Hemminger ; James E . J . Bottomley 
> ;
> Martin K . Petersen ; 
> de...@linuxdriverproject.org; linux-
> s...@vger.kernel.org; linux-ker...@vger.kernel.org
> Cc: Long Li 
> Subject: [PATCH v2] storvsc: Set up correct queue depth values for IDE devices
> 
> From: Long Li 
> 
> Unlike SCSI and FC, we don't use multiple channels for IDE.
> Also fix the calculation for sub-channels.
> 
> Change log:
> v2: Addressed comment on incorrect number of sub-channels.
> (Michael Kelley )
> 
> Signed-off-by: Long Li 

Reviewed-by: Michael Kelley 

> ---
>  drivers/scsi/storvsc_drv.c | 7 +--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 8c51d628b52e..a2ec0bc9e9fa 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1722,11 +1722,14 @@ static int storvsc_probe(struct hv_device *device,
>   max_targets = STORVSC_MAX_TARGETS;
>   max_channels = STORVSC_MAX_CHANNELS;
>   /*
> -  * On Windows8 and above, we support sub-channels for storage.
> +  * On Windows8 and above, we support sub-channels for storage
> +  * on SCSI and FC controllers.
>* The number of sub-channels offerred is based on the number of
>* VCPUs in the guest.
>*/
> - max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
> + if (!dev_is_ide)
> + max_sub_channels =
> + (num_cpus - 1) / storvsc_vcpus_per_sub_channel;
>   }
> 
>   scsi_driver.can_queue = (max_outstanding_req_per_channel *
> --
> 2.14.1

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