diff mbox series

[V3,07/16] powerpc/vas: Define QoS credit flag to allocate window

Message ID 90328d5aa92016434f3061ec7cadc812ea2c5dbc.camel@linux.ibm.com
State Superseded
Headers show
Series Enable VAS and NX-GZIP support on powerVM | expand

Commit Message

Haren Myneni April 17, 2021, 9:06 p.m. UTC
pHyp introduces two different type of credits: Default and Quality
of service (QoS).

The total number of default credits available on each LPAR depends
on CPU resources configured. But these credits can be shared or
over-committed across LPARs in shared mode which can result in
paste command failure (RMA_busy). To avoid NX HW contention, phyp
introduces QoS credit type which makes sure guaranteed access to NX
resources. The system admins can assign QoS credits for each LPAR
via HMC.

Default credit type is used to allocate a VAS window by default as
on powerVM implementation. But the process can pass VAS_WIN_QOS_CREDITS
flag with VAS_TX_WIN_OPEN ioctl to open QoS type window.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/uapi/asm/vas-api.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Nicholas Piggin May 10, 2021, 5:54 a.m. UTC | #1
Excerpts from Haren Myneni's message of April 18, 2021 7:06 am:
> 

> pHyp introduces two different type of credits: Default and Quality

> of service (QoS).

> 

> The total number of default credits available on each LPAR depends

> on CPU resources configured. But these credits can be shared or

> over-committed across LPARs in shared mode which can result in

> paste command failure (RMA_busy). To avoid NX HW contention, phyp

> introduces QoS credit type which makes sure guaranteed access to NX

> resources. The system admins can assign QoS credits for each LPAR

> via HMC.

> 

> Default credit type is used to allocate a VAS window by default as

> on powerVM implementation. But the process can pass VAS_WIN_QOS_CREDITS



There's some interchanging of pHyp and PowerVM in the series.

PowerVM is probably the better term to use, with uppercase P.
Unless you mean PAPR or pseries etc.

I think you can say the PAPR VAS spec has two different types of 
credits, rather than say a specific hypervisor is introducing them.

> flag with VAS_TX_WIN_OPEN ioctl to open QoS type window.

> 

> Signed-off-by: Haren Myneni <haren@linux.ibm.com>

> ---

>  arch/powerpc/include/uapi/asm/vas-api.h | 6 +++++-

>  1 file changed, 5 insertions(+), 1 deletion(-)

> 

> diff --git a/arch/powerpc/include/uapi/asm/vas-api.h b/arch/powerpc/include/uapi/asm/vas-api.h

> index ebd4b2424785..eb7c8694174f 100644

> --- a/arch/powerpc/include/uapi/asm/vas-api.h

> +++ b/arch/powerpc/include/uapi/asm/vas-api.h

> @@ -13,11 +13,15 @@

>  #define VAS_MAGIC	'v'

>  #define VAS_TX_WIN_OPEN	_IOW(VAS_MAGIC, 0x20, struct vas_tx_win_open_attr)

>  

> +/* Flags to VAS TX open window ioctl */

> +/* To allocate a window with QoS credit, otherwise default credit is used */

> +#define	VAS_WIN_QOS_CREDITS	0x0000000000000001

> +

>  struct vas_tx_win_open_attr {


Some consistency of naming might help, VAS_TX_WIN_FLAG_QOS_CREDIT.

>  	__u32	version;

>  	__s16	vas_id;	/* specific instance of vas or -1 for default */

>  	__u16	reserved1;

> -	__u64	flags;	/* Future use */

> +	__u64	flags;

>  	__u64	reserved2[6];

>  };

>  

> -- 

> 2.18.2

> 

> 

>
Haren Myneni May 11, 2021, 2:12 a.m. UTC | #2
On Mon, 2021-05-10 at 15:54 +1000, Nicholas Piggin wrote:
> Excerpts from Haren Myneni's message of April 18, 2021 7:06 am:

> > pHyp introduces two different type of credits: Default and Quality

> > of service (QoS).

> > 

> > The total number of default credits available on each LPAR depends

> > on CPU resources configured. But these credits can be shared or

> > over-committed across LPARs in shared mode which can result in

> > paste command failure (RMA_busy). To avoid NX HW contention, phyp

> > introduces QoS credit type which makes sure guaranteed access to NX

> > resources. The system admins can assign QoS credits for each LPAR

> > via HMC.

> > 

> > Default credit type is used to allocate a VAS window by default as

> > on powerVM implementation. But the process can pass

> > VAS_WIN_QOS_CREDITS

> 

> There's some interchanging of pHyp and PowerVM in the series.

> 

> PowerVM is probably the better term to use, with uppercase P.

> Unless you mean PAPR or pseries etc.

> 

> I think you can say the PAPR VAS spec has two different types of 

> credits, rather than say a specific hypervisor is introducing them.


DEF and QoS credits types are introduced by the hypervisor, not VAS
PAPR. We did not have these types on powerNV. 

> 

> > flag with VAS_TX_WIN_OPEN ioctl to open QoS type window.

> > 

> > Signed-off-by: Haren Myneni <haren@linux.ibm.com>

> > ---

> >  arch/powerpc/include/uapi/asm/vas-api.h | 6 +++++-

> >  1 file changed, 5 insertions(+), 1 deletion(-)

> > 

> > diff --git a/arch/powerpc/include/uapi/asm/vas-api.h

> > b/arch/powerpc/include/uapi/asm/vas-api.h

> > index ebd4b2424785..eb7c8694174f 100644

> > --- a/arch/powerpc/include/uapi/asm/vas-api.h

> > +++ b/arch/powerpc/include/uapi/asm/vas-api.h

> > @@ -13,11 +13,15 @@

> >  #define VAS_MAGIC	'v'

> >  #define VAS_TX_WIN_OPEN	_IOW(VAS_MAGIC, 0x20, struct

> > vas_tx_win_open_attr)

> >  

> > +/* Flags to VAS TX open window ioctl */

> > +/* To allocate a window with QoS credit, otherwise default credit

> > is used */

> > +#define	VAS_WIN_QOS_CREDITS	0x0000000000000001

> > +

> >  struct vas_tx_win_open_attr {

> 

> Some consistency of naming might help, VAS_TX_WIN_FLAG_QOS_CREDIT.


Sure, will change.
> 

> >  	__u32	version;

> >  	__s16	vas_id;	/* specific instance of vas or -1 for

> > default */

> >  	__u16	reserved1;

> > -	__u64	flags;	/* Future use */

> > +	__u64	flags;

> >  	__u64	reserved2[6];

> >  };

> >  

> > -- 

> > 2.18.2

> > 

> > 

> >
diff mbox series

Patch

diff --git a/arch/powerpc/include/uapi/asm/vas-api.h b/arch/powerpc/include/uapi/asm/vas-api.h
index ebd4b2424785..eb7c8694174f 100644
--- a/arch/powerpc/include/uapi/asm/vas-api.h
+++ b/arch/powerpc/include/uapi/asm/vas-api.h
@@ -13,11 +13,15 @@ 
 #define VAS_MAGIC	'v'
 #define VAS_TX_WIN_OPEN	_IOW(VAS_MAGIC, 0x20, struct vas_tx_win_open_attr)
 
+/* Flags to VAS TX open window ioctl */
+/* To allocate a window with QoS credit, otherwise default credit is used */
+#define	VAS_WIN_QOS_CREDITS	0x0000000000000001
+
 struct vas_tx_win_open_attr {
 	__u32	version;
 	__s16	vas_id;	/* specific instance of vas or -1 for default */
 	__u16	reserved1;
-	__u64	flags;	/* Future use */
+	__u64	flags;
 	__u64	reserved2[6];
 };