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Add PFC Deadlock Detection timer granularity attributes #2250

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Add PFC Deadlock Detection timer granularity attributes #2250

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b5873ad
Add PFC Deadlock Detection timer granularity attributes
pinky-nexthop Feb 6, 2026
b55853a
Clarify timer granularity attribute documentation
pinky-nexthop Feb 7, 2026
57b6c5f
Simplify timer granularity documentation
pinky-nexthop Feb 7, 2026
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11 changes: 11 additions & 0 deletions inc/saiport.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2925,6 +2925,17 @@ typedef enum _sai_port_attr_t
*/
SAI_PORT_ATTR_LINK_UP_DEBOUNCE_TIMEOUT,

/**
* @brief Port PFC Deadlock Detection timer granularity in milliseconds.
*
* Specifies the hardware timer granularity for PFC deadlock detection.
*
* @type sai_map_list_t
* @flags CREATE_AND_SET
* @default empty
*/
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@kperumalbfn kperumalbfn Feb 6, 2026

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@pinky-nexthop why list of granularities?

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@pinky-nexthop pinky-nexthop Feb 8, 2026

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Good point. Removed.

SAI_PORT_ATTR_PFC_TC_DLD_TIMER_INTERVAL,
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@kperumalbfn kperumalbfn Feb 6, 2026

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could you also add the unit of the granularity? Is this in milliseconds?

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@pinky-nexthop pinky-nexthop Feb 8, 2026

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Yes, updated. Thanks.


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@eddyk-nvidia eddyk-nvidia Mar 12, 2026

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Real use-case of different timer intervals for different ports ? For uplink and downlink for example ?

/**
* @brief End of attributes
*/
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11 changes: 11 additions & 0 deletions inc/saiswitch.h
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Expand Up @@ -3550,6 +3550,17 @@ typedef enum _sai_switch_attr_t
*/
SAI_SWITCH_ATTR_LINK_UP_DEBOUNCE_TIMEOUT,

/**
* @brief PFC Deadlock Detection timer granularity in milliseconds.
*
* Specifies the hardware timer granularity for PFC deadlock detection.
*
* @type sai_map_list_t
* @flags CREATE_AND_SET
* @default empty
*/
SAI_SWITCH_ATTR_PFC_TC_DLD_TIMER_INTERVAL,
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@eddyk-nvidia eddyk-nvidia Mar 12, 2026

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Why not to use the existing SAI_SWITCH_ATTR_PFC_TC_DLD_INTERVAL SAI attribute ?

We will have 2 now : SAI_SWITCH_ATTR_PFC_TC_DLD_INTERVAL (old) and SAI_SWITCH_ATTR_PFC_TC_DLD_TIMER_INTERVAL (new)

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@pinky-nexthop pinky-nexthop Mar 12, 2026

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SAI_SWITCH_ATTR_PFC_TC_DLD_INTERVAL and SAI_PORT_ATTR_PFC_TC_DLD_INTERVAL are existing attributes that define the detection time to trigger deadlock state on a port/queue.
However, the new proposal SAI_SWITCH_ATTR_PFC_TC_DLD_TIMER_INTERVAL is for setting the granularity of the h/w timers. For example, broadcom chips support granularity of 1ms, 10ms and 100ms. If granularity is set to 10ms, then h/w can only program detection timer range between 10-150ms. Similarly, if granularity is set to 100ms, then h/w can only program detection timer range between 100-1500ms.
therefore, a new SAI attribute is required to dynamically tune the detection timer range based on this new attribute.

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@rck-innovium rck-innovium Mar 12, 2026 •
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  • I agree with @eddyk-nvidia; this can be managed by the SAI/SDK implementation using the existing SAI attributes. For the above e.g., the SDK can choose to return the range {1 to 1500} as part of the get on SAI_PORT_ATTR_PFC_TC_DLD_INTERVAL_RANGE. When the user sets SAI_SWITCH_ATTR_PFC_TC_DLD_INTERVAL as 1500, the SDK can internally configure the h/w timer granularity to 100ms.
  • Reason: The above relationship between detection time and timer interval seems platform specific: that the detection interval must be <= 10 * timer_interval.


/**
* @brief End of attributes
*/
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