Hi,
I’m trying power saving feature in my server with intel sapphire rapid CPU. With “tsx=on” kernel parameter, I have both
rtm and waitpkg available in CPU flag.
I tried rte_power_monitor_multi API to monitor on multiple address, but it never enters C0.2/C0.1 state.
To find the reason I patched the code to return the transaction abort code as below:
/* transaction abort, possible write to one of wait addresses */
if (rc != RTE_XBEGIN_STARTED)
- return 0;
+ return rc;
and it turn out that RTM transaction always aborted with 0 (a few times with 4 or 6 also, which I think maybe expected due to memory change of monitored addresses).
I found some explanation of the abort state here:
For abort code 0, it just say one example (CPUID used within transcation), but it seems CPUID is not used within rte_power_monitor_multi.
I also tried rte_power_pause and rte_power_monitor, both works as expected, CPU enters C0.2 state (checked by
perf stat --e r20ec -C xx)
Now, I don’t know why the RTM transaction aborted with 0 and don’t know how to debug it.
Can anyone throw some light on this?
Thank you.
Br, Xiaoping