[EXTERNAL] Re: [PATCH v4 1/1] dmadev: support priority configuration

[Vamsi Krishna Attunuru]

Thank you, Feng, for reviewing the patch. I agree with the comments that are suggested, will rework, and send next version.

Regards
Vamsi

>-----Original Message-----
>From: fengchengwen <fengchengwen at huawei.com>
>Sent: Tuesday, October 8, 2024 8:07 AM
>To: Vamsi Krishna Attunuru <vattunuru at marvell.com>;
>thomas at monjalon.net; bruce.richardson at intel.com;
>mb at smartsharesystems.com
>Cc: dev at dpdk.org; kevin.laatz at intel.com; Jerin Jacob <jerinj at marvell.com>;
>conor.walsh at intel.com; Gowrishankar Muthukrishnan
><gmuthukrishn at marvell.com>; Vidya Sagar Velumuri
><vvelumuri at marvell.com>; g.singh at nxp.com; sachin.saxena at oss.nxp.com;
>hemant.agrawal at nxp.com; Amit Prakash Shukla
><amitprakashs at marvell.com>
>Subject: [EXTERNAL] Re: [PATCH v4 1/1] dmadev: support priority
>configuration
>
>Hi, Sorry to reply now, because I just got back from our National Day vacation.
>From the commit it seem confused about the dmadev and HW channel,
>Current one dmadev is corresponding a HW channel if its a hardware device.
>So I suggest try not 
>Hi,
>
>Sorry to reply now, because I just got back from our National Day vacation.
>
>From the commit it seem confused about the dmadev and HW channel,
>Current one dmadev is corresponding a HW channel if its a hardware device.
>So I suggest try not to mention HW channel, but the dmadev or DMA device.
>
>Suggest the tile of the commit: dmadev: support strict priority configuration
>
>On 2024/10/3 19:53, Vamsi Krishna wrote:
>> From: Vamsi Attunuru <vattunuru at marvell.com>
>>
>> Some DMA controllers offer the ability to configure priority level for
>> the hardware command queues, allowing for the prioritization of
>
>Let align the queues to channels
>for the hardware DMA channels,
>
>> DMA command execution based on queue importance.
>
>based on channel importance.
>
>>
>> This patch introduces the necessary fields in the dmadev structures to
>> retrieve information about the hardware-supported priority levels and
>> to enable priority configuration from the application.
>
>This patch supports such strict priority configuration. If the dmadev supports,
>it should declared the capability flag RTE_DMA_CAPA_PRI_POLICY_SP, then
>application could enable strict priority configuration.
>
>>
>> Signed-off-by: Vamsi Attunuru <vattunuru at marvell.com>
>> Signed-off-by: Amit Prakash Shukla <amitprakashs at marvell.com>
>> ---
>> V4 changes:
>> * Rebased onto the latest
>>
>> V3 changes:
>> * Corrected patch title
>>
>> V2 changes:
>> * Reverted removed text from release_24_11.rst
>>
>> V1 changes:
>> * Added trace support
>> * Added new capability flag
>>
>> Deprecation notice:
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__patches.dpdk.org_
>> project_dpdk_patch_20240730144612.2132848-2D1-2Damitprakashs-
>40marvell
>>
>.com_&d=DwICaQ&c=nKjWec2b6R0mOyPaz7xtfQ&r=WllrYaumVkxaWjgKto6E
>_rtDQshh
>> Ihik2jkvzFyRhW8&m=Bs48xsaE5RgtPTZ5CoHM0E7Jn1c5no1ae-
>iuOVu8sJXD2414W2oU
>>
>rkmSASXpK1bA&s=RCRKJ2naUgpLqMM_qB_pD6hc6bFN7Tbl4XCEByoG9Cw&
>e=
>>
>> * Assuming we do not anticipate any advanced scheduling schemes for
>dmadev queues,
>>   this patch is intended to support a strict priority scheme.
>>
>>  doc/guides/rel_notes/release_24_11.rst |  8 ++++++++
>>  lib/dmadev/rte_dmadev.c                | 15 +++++++++++++++
>>  lib/dmadev/rte_dmadev.h                | 21 +++++++++++++++++++++
>>  lib/dmadev/rte_dmadev_trace.h          |  2 ++
>>  4 files changed, 46 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/release_24_11.rst
>> b/doc/guides/rel_notes/release_24_11.rst
>> index e0a9aa55a1..9672d8c679 100644
>> --- a/doc/guides/rel_notes/release_24_11.rst
>> +++ b/doc/guides/rel_notes/release_24_11.rst
>> @@ -67,6 +67,11 @@ New Features
>>
>>    The new statistics are useful for debugging and profiling.
>>
>> +* **Added strict priority capability flag in dmadev.**
>> +
>> +  Added new capability flag ``RTE_DMA_CAPA_PRI_POLICY_SP`` to check
>> + if the  DMA device supports assigning fixed priority to its
>> + channels, allowing  for better control over resource allocation and
>scheduling.
>
>Please refine:
>
>Add strict priority capability for dmadev.
>
>Added new capability flag ``RTE_DMA_CAPA_PRI_POLICY_SP`` to check if the
>DMA device supports assigned fixed priority, allowing for better control over
>resource allocation and scheduling.
>
>>
>>  Removed Items
>>  -------------
>> @@ -112,6 +117,9 @@ ABI Changes
>>     Also, make sure to start the actual text at the margin.
>>     =======================================================
>>
>> +* dmadev: Added ``nb_priorities`` field to ``rte_dma_info`` structure
>> +and
>> +  ``priority`` field to ``rte_dma_conf`` structure to get device
>> +supported
>> +  priority levels and configure required priority from the application.
>>
>>  Known Issues
>>  ------------
>> diff --git a/lib/dmadev/rte_dmadev.c b/lib/dmadev/rte_dmadev.c index
>> 845727210f..3d9063dee3 100644
>> --- a/lib/dmadev/rte_dmadev.c
>> +++ b/lib/dmadev/rte_dmadev.c
>> @@ -497,6 +497,21 @@ rte_dma_configure(int16_t dev_id, const struct
>rte_dma_conf *dev_conf)
>>  		return -EINVAL;
>>  	}
>>
>> +	if (dev_conf->priority && !(dev_info.dev_capa &
>RTE_DMA_CAPA_PRI_POLICY_SP)) {
>> +		RTE_DMA_LOG(ERR, "Device %d don't support prioritization",
>dev_id);
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (dev_info.nb_priorities == 1) {
>> +		RTE_DMA_LOG(ERR, "Device %d must support more than 1
>priority, or else 0", dev_id);
>> +		return -EINVAL;
>> +	}
>
>Please consider other driver which don't set nb_priorities, then it will failed in
>the above branch.
>
>Suggest add this verify in rte_dma_info_get(), make sure that this field should
>be > 1 if it supported PRI_POLICY_SP.
>
>> +
>> +	if (dev_info.nb_priorities && (dev_conf->priority >=
>dev_info.nb_priorities)) {
>> +		RTE_DMA_LOG(ERR, "Device %d configure invalid priority",
>dev_id);
>> +		return -EINVAL;
>> +	}
>> +
>>  	if (*dev->dev_ops->dev_configure == NULL)
>>  		return -ENOTSUP;
>>  	ret = (*dev->dev_ops->dev_configure)(dev, dev_conf, diff --git
>> a/lib/dmadev/rte_dmadev.h b/lib/dmadev/rte_dmadev.h index
>> 5474a5281d..e5f730c327 100644
>> --- a/lib/dmadev/rte_dmadev.h
>> +++ b/lib/dmadev/rte_dmadev.h
>> @@ -268,6 +268,16 @@ int16_t rte_dma_next_dev(int16_t start_dev_id);
>>  #define RTE_DMA_CAPA_OPS_COPY_SG	RTE_BIT64(33)
>>  /** Support fill operation. */
>>  #define RTE_DMA_CAPA_OPS_FILL		RTE_BIT64(34)
>> +/** Support strict prioritization at DMA HW channel level
>> + *
>> + * If device supports HW channel prioritization then application
>> +could
>> + * assign fixed priority to the DMA HW channel using 'priority' field
>> +in
>> + * struct rte_dma_conf. Number of supported priority levels will be
>> +known
>> + * from 'nb_priorities' field in struct rte_dma_info.
>> + *
>> + * DMA devices which support prioritization can advertise this capability.
>
>How about:
>Support strict priority scheduling.
>
>Application could assign fixed priority to the DMA device using 'priority' field in
>struct rte_dma_conf. Number of supported priority levels will be known from
>'nb_priorities'
>field in struct rte_dma_info.
>
>> + */
>> +#define RTE_DMA_CAPA_PRI_POLICY_SP	RTE_BIT64(35)
>
>This capa is a control plane flag, so please add after
>RTE_DMA_CAPA_M2D_AUTO_FREE.
>
>>  /**@}*/
>>
>>  /**
>> @@ -297,6 +307,10 @@ struct rte_dma_info {
>>  	int16_t numa_node;
>>  	/** Number of virtual DMA channel configured. */
>>  	uint16_t nb_vchans;
>> +	/** Number of priority levels (must be > 1), if supported by DMA HW
>channel.
>> +	 * 0 otherwise.
>
>How about "Number of priority levels (must be > 1) if supported priority
>scheduling."
>
>A DMA HW channel was just one dmadev, suggest don't introduce it.
>
>> +	 */
>> +	uint16_t nb_priorities;
>>  };
>>
>>  /**
>> @@ -332,6 +346,13 @@ struct rte_dma_conf {
>>  	 * @see RTE_DMA_CAPA_SILENT
>>  	 */
>>  	bool enable_silent;
>> +	/* The priority of the DMA HW channel.
>> +	 * This value cannot be greater than or equal to the field 'nb_priorities'
>> +	 * of struct rte_dma_info which get from rte_dma_info_get().
>> +	 * Among the values between '0' and 'nb_priorities - 1', lowest value
>> +	 * indicates higher priority and vice-versa.
>
>How about (you could retouch it. I'm not a native English speaker.):
>The priority of the DMA device.
>If the the DMA device don't support priority scheduling, this value should be
>zero.
>Otherwise, the value should lower than the field 'nb_priorities' of struct
>rte_dma_info which get from rte_dma_info_get(). And also lowest value
>indicates higher priority and vice-versa.
>
>> +	 */
>> +	uint16_t priority;
>>  };
>>
>>  /**
>> diff --git a/lib/dmadev/rte_dmadev_trace.h
>> b/lib/dmadev/rte_dmadev_trace.h index e55c4c6091..be089c065c 100644
>> --- a/lib/dmadev/rte_dmadev_trace.h
>> +++ b/lib/dmadev/rte_dmadev_trace.h
>> @@ -35,6 +35,7 @@ RTE_TRACE_POINT(
>>  	rte_trace_point_emit_u16(dev_info->max_sges);
>>  	rte_trace_point_emit_i16(dev_info->numa_node);
>>  	rte_trace_point_emit_u16(dev_info->nb_vchans);
>> +	rte_trace_point_emit_u16(dev_info->nb_priorities);
>>  )
>>
>>  RTE_TRACE_POINT(
>> @@ -48,6 +49,7 @@ RTE_TRACE_POINT(
>>  	int enable_silent = (int)dev_conf->enable_silent;
>>  	rte_trace_point_emit_i16(dev_id);
>>  	rte_trace_point_emit_u16(dev_conf->nb_vchans);
>> +	rte_trace_point_emit_u16(dev_conf->priority);
>>  	rte_trace_point_emit_int(enable_silent);
>>  	rte_trace_point_emit_int(ret);
>>  )
>
>Please also modify dma_capability_name and dmadev_handle_dev_info,