Public bug reported:
SRU Justification:
[Impact]
Currently, there is no method to keep track of the cycle count when an event is
being monitored. And since cycle count increments quickly, the 32-bit counter
values could wrap around and hence support for 64-bit counters is also needed
for the same.
[Fix]
Expose 2 additional sysfs entries: count_clock and use_odd_counter. These
fields are supported in BlueField-3 PMC hardware and each bit in count_clock
corresponds to each counter, while each bit in use_odd_counter corresponds to
an even counter.Exposing these fields will allow the user to program any
counter of choice to monitor the cycle count for the required duration.
Similarly, use_odd_counter can be set to couple 2 adjacent odd and even
counters to form a 64-bit counter.
[Test Case]
1. Verify that count_clock and use_odd_counter sysfs entries are created for
each BlueField-3 HW block. These are not supported by BlueField-1 or
BlueField-2 HW.
2. Set any bit in count_clock and check if the corresponding counter values
increment after enabling.
3. Set any bit in use_odd_counter and check if the cycle count increments on 2
counters with the odd counter being the lower 32 bits and the even counter
being the upper 32 bits.
[Regression Potential]
Can be considered minimal.
** Affects: linux-bluefield (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2042525
Title:
mlxbf-pmc: Support 64-bit counter and counting cycles
Status in linux-bluefield package in Ubuntu:
New
Bug description:
SRU Justification:
[Impact]
Currently, there is no method to keep track of the cycle count when an event
is being monitored. And since cycle count increments quickly, the 32-bit
counter values could wrap around and hence support for 64-bit counters is also
needed for the same.
[Fix]
Expose 2 additional sysfs entries: count_clock and use_odd_counter. These
fields are supported in BlueField-3 PMC hardware and each bit in count_clock
corresponds to each counter, while each bit in use_odd_counter corresponds to
an even counter.Exposing these fields will allow the user to program any
counter of choice to monitor the cycle count for the required duration.
Similarly, use_odd_counter can be set to couple 2 adjacent odd and even
counters to form a 64-bit counter.
[Test Case]
1. Verify that count_clock and use_odd_counter sysfs entries are created for
each BlueField-3 HW block. These are not supported by BlueField-1 or
BlueField-2 HW.
2. Set any bit in count_clock and check if the corresponding counter values
increment after enabling.
3. Set any bit in use_odd_counter and check if the cycle count increments on
2 counters with the odd counter being the lower 32 bits and the even counter
being the upper 32 bits.
[Regression Potential]
Can be considered minimal.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-bluefield/+bug/2042525/+subscriptions
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