Intel® Xeon® Processor E5-2600 Product Family Uncore Performance Monitoring
40
Reference Number: 327043-001
RxR_IRQ_RETRY
• Title:
Ingress Request Queue Rejects
• Category:
INGRESS_RETRY Events
• Event Code:
0x32
• Max. Inc/Cyc:
1,
Register Restrictions:
0-1
• Definition:
Table 2-26. Unit Masks for RxR_IPQ_RETRY
Extension
umask
[15:8]
Description
ANY
bxxxxxxx1
Any Reject:
Counts the number of times that a request form the IPQ was retried
because of a TOR reject. TOR rejects from the IPQ can be caused by
the Egress being full or Address Conflicts.
FULL
bxxxxxx1x
No Egress Credits:
Counts the number of times that a request form the IPQ was retried
because of a TOR reject from the Egress being full. IPQ requests
make use of the AD Egress for regular responses, the BL egress to
forward data, and the AK egress to return credits.
ADDR_CONFLICT
bxxxxx1xx
Address Conflict:
Counts the number of times that a request form the IPQ was retried
because of a TOR reject from an address conflicts. Address conflicts
out of the IPQ should be rare. They will generally only occur if two
different sockets are sending requests to the same address at the
same time. This is a true "conflict" case, unlike the IPQ Address
Conflict which is commonly caused by prefetching characteristics.
QPI_CREDITS
bxxx1xxxx
No Intel® QPI Credits
Table 2-27. Unit Masks for RxR_IRQ_RETRY (Sheet 1 of 2)
Extension
umask
[15:8]
Description
ANY
bxxxxxxx1
Any Reject:
Counts the number of IRQ retries that occur. Requests from the IRQ
are retried if they are rejected from the TOR pipeline for a variety of
reasons. Some of the most common reasons include if the Egress is
full, there are no RTIDs, or there is a Physical Address match to
another outstanding request.
FULL
bxxxxxx1x
No Egress Credits:
Counts the number of times that a request from the IRQ was retried
because it failed to acquire an entry in the Egress. The egress is the
buffer that queues up for allocating onto the ring. IRQ requests can
make use of all four rings and all four Egresses. If any of the queues
that a given request needs to make use of are full, the request will be
retried.
ADDR_CONFLICT
bxxxxx1xx
Address Conflict:
Counts the number of times that a request from the IRQ was retried
because of an address match in the TOR. In order to maintain
coherency, requests to the same address are not allowed to pass
each other up in the Cbo. Therefore, if there is an outstanding
request to a given address, one cannot issue another request to that
address until it is complete. This comes up most commonly with
prefetches. Outstanding prefetches occasionally will not complete
their memory fetch and a demand request to the same address will
then sit in the IRQ and get retried until the prefetch fills the data into
the LLC. Therefore, it will not be uncommon to see this case in high
bandwidth streaming workloads when the LLC Prefetcher in the core
is enabled.
