Introduce a PMU device named cpum_cf_diag. It extracts the
values of all counters in all authorized counter sets and stores
them as event raw data. This is done with the STORE CPU COUNTER
MULTIPLE instruction to speed up access. All counter sets
fit into one buffer. The values of each counter are taken
when the event is started on the performance sub-system and when
the event is stopped.
This results in counter values available at the start and
at the end of the measurement time frame. The difference is
calculated for each counter. The differences of all
counters are then saved as event raw data in the perf.data
file.
The counter values are accompanied by the time stamps
when the counter set was started and when the counter set
was stopped. This data is part of a trailer entry which
describes the time frame, counter set version numbers,
CPU speed, and machine type for later analysis.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce the ctr_stcctm() function as wrapper function to extract counters
from a particular counter set. Note that the counter set is part of the
stcctm instruction opcode, few indirections are necessary to specify the
counter set as variable.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
A preparation to move out common CPU-MF counter facility support
functions, first introduce a function that indicates whether the
support is ready to use.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce a minimal interface for doing counter measurements of small
units of work within the kernel. Use the kernel_cpumcf_begin() function
start a measurement session and, later, stop it with kernel_cpumcf_end().
During the measreument session, you can enable and start/stop counter sets
by using ctr_set_* functions. To make these changes effective use the
lcctl() function. You can then use the ecctr() function to extract counters
from the different counter sets.
Please note that you have to check whether the counter sets to be enabled
are authorized.
Note that when a measurement session is active, other users cannot perform
counter measurements. In such cases, kernel_cpumcf_begin() indicates this
with returning -EBUSY. If the counter facility is not available,
kernel_cpumcf_begin() returns -ENODEV.
Note that this interface is restricted to the current CPU and, thus,
preemption must be turned off.
Example:
u32 state, err;
u64 cycles, insn;
err = kernel_cpumcf_begin();
if (err)
goto out_busy;
state = 0;
ctr_set_enable(&state, CPUMF_CTR_SET_BASIC);
ctr_set_start(&state, CPUMF_CTR_SET_BASIC);
err = lcctl(state);
if (err)
goto ;
/* ... do your work ... */
ctr_set_stop(&state, CPUMF_CTR_SET_BASIC);
err = lcctl(state);
if (err)
goto out;
cycles = insn = 0;
ecctr(0, &cycles);
ecctr(1, &insn);
/* ... */
kernel_cpumcf_end();
out_busy:
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
During a __kernel_cpumcf_begin()/end() session, save measurement alerts
for the counter facility in the per-CPU cpu_cf_events variable.
Users can obtain and, optionally, clear the alerts by calling
kernel_cpumcf_alert() to specifically handle alerts.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make the struct cpu_cf_events and the respective per-CPU variable available
to in-kernel users. Access to this per-CPU variable shall be done between
the calls to __kernel_cpumcf_begin() and __kernel_cpumcf_end().
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Prepare the counter facility support to be used by other in-kernel
users. The first step introduces the __kernel_cpumcf_begin() and
__kernel_cpumcf_end() functions to reserve the counter facility
for doing measurements and to release after the measurements are
done.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Move counter set specific controls and functions to the asm/cpu_mcf.h
header file containg all counter facility support definitions. Also
adapt few variable names and header file includes. No functional changes.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
