[Skiboot] [PATCH v3 0/7] skiboot: OPAL support for IMC trace-mode

Stewart Smith stewart at linux.vnet.ibm.com
Fri Mar 29 16:34:23 AEDT 2019

Anju T Sudhakar <anju at linux.vnet.ibm.com> writes:
> Hi Stewart,
> On 3/29/19 10:23 AM, Stewart Smith wrote:
>> Anju T Sudhakar <anju at linux.vnet.ibm.com> writes:
>>> IMC (In-Memory collection counters) is a hardware monitoring facility
>>> that collects large number of hardware performance events.
>>> POWER9 support two modes for IMC which are the Accumulation mode and
>>> Trace mode. In Accumulation mode, event counts are accumulated in system
>>> Memory. Hypervisor then reads the posted counts periodically or when
>>> requested. In IMC Trace mode, the 64 bit trace scom value is initialized
>>> with the event information. The CPMC*SEL and CPMC_LOAD in the trace scom, specifies
>>> the event to be monitored and the sampling duration. On each overflow in the
>>> CPMC*SEL, hardware snapshots the program counter along with event counts
>>> and writes into memory pointed by LDBAR. LDBAR has bits to indicate whether
>>> hardware is configured for accumulation or trace mode.
>>> Currently the event monitored for trace-mode is fixed as cycle.
>> I've merged the patch series to master as of
>> 027d87475eff7d57b1bf996e4d633e880f571a22 and it's in v6.3-rc1.
> Thanks.
>> I'm not sure why you CC'd stable on the ptach series though. Since it's
>> new function, it doesn't qualify for a stable branch.
> Sorry, I've cc'ed stable by mistake. I informed Vasant on this.

No worries.

Stewart Smith
OPAL Architect, IBM.

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