Uncore Manual

Uncore Performance Monitoring
Cacheing Agent (Cbo) Performance Monitoring
48 Reference Number: 329468-002
RxR_ISMQ_RETRY
• Title: ISMQ Retries
• Category: INGRESS_RETRY Events
• Event Code: 0x33
• Max. Inc/Cyc:. 1, Register Restrictions: 0-1
• Definition: Number of times a transaction flowing through the ISMQ had to retry. Transaction pass
through the ISMQ as responses for requests that already exist in the Cbo. Some examples include:
when data is returned or when snoop responses come back from the cores.
RTID bxxxx1xxx No RTIDs
Counts the number of times that requests from the IRQ were
retried because there were no RTIDs available. RTIDs are
required after a request misses the LLC and needs to send
snoops and/or requests to memory. If there are no RTIDs
available, requests will queue up in the IRQ and retry until one
becomes available. Note that there are multiple RTID pools for
the different sockets. There may be cases where the local RTIDs
are all used, but requests destined for remote memory can still
acquire an RTID because there are remote RTIDs available. This
event does not provide any filtering for this case.
QPI_CREDITS bxxx1xxxx No QPI Credits
Number of requests rejects because of lack of QPI Ingress
credits. These credits are required in order to send transactions
to the QPI agent. Please see the QPI_IGR_CREDITS events for
more information.
IIO_CREDITS bxx1xxxxx No IIO Credits
Number of times a request attempted to acquire the NCS/NCB
credit for sending messages on BL to the IIO. There is a single
credit in each CBo that is shared between the NCS and NCB
message classes for sending transactions on the BL ring (such as
read data) to the IIO.
Table 2-31. Unit Masks for RxR_ISMQ_RETRY
Extension
umask
[15:8]
Description
ANY bxxxxxxx1 Any Reject
Counts the total number of times that a request from the ISMQ
retried because of a TOR reject. ISMQ requests generally will not
need to retry (or at least ISMQ retries are less common than
IRQ retries). ISMQ requests will retry if they are not able to
acquire a needed Egress credit to get onto the ring, or for cache
evictions that need to acquire an RTID. Most ISMQ requests
already have an RTID, so eviction retries will be less common
here.
FULL bxxxxxx1x No Egress Credits
Counts the number of times that a request from the ISMQ
retried because of a TOR reject caused by a lack of Egress
credits. The egress is the buffer that queues up for allocating
onto the ring. If any of the Egress queues that a given request
needs to make use of are full, the request will be retried.
RTID bxxxx1xxx No RTIDs
Counts the number of times that a request from the ISMQ
retried because of a TOR reject caused by no RTIDs. M-state
cache evictions are serviced through the ISMQ, and must
acquire an RTID in order to write back to memory. If no RTIDs
are available, they will be retried.
QPI_CREDITS bxxx1xxxx No QPI Credits
Table 2-30. Unit Masks for RxR_IRQ_RETRY
Extension
umask
[15:8]
Description