Table 9 Information in alat Measurement Reports
Column | Description | |
|
| |
% Total Sampled ALAT | Percent of the total for <metric> attributable to a given program object. The <metric> is the | |
Misses | same as the <metric> HP Caliper uses for sorting, except when the sort metric is address, | |
| in which case sampled misses is used. | |
|
| |
Cumulat % of Total | A running sum of the percent of total for <metric> accounted for by the given program object | |
| and those listed above it. | |
|
| |
Sampled ALAT Misses | Total number of sampled failed chk.a/ld.c instructions attributed to the given program | |
| object. | |
|
| |
Kernel Thread | Kernel Thread ID suffixed with the the name of the routine that the thread will execute once | |
Identification Number | it is created. | |
|
| |
Load Module | A shared library or the main executable. | |
|
| |
Function | Routine from your application. | |
|
| |
File | Source file associated with a function. | |
|
| |
Line | The column contains one of these: | |
Slot | • A | |
Col,Offset | ||
• An instruction slot number for rows showing instructions not on a bundle boundary | ||
| ||
| • A | |
| function for rows showing instructions on a bundle boundary | |
| Column and line numbers are preceded by “~” when they are approximate due to | |
| optimization. | |
|
| |
>Statement | The column contains either a source statement, preceded by “>”, or a disassembled instruction. | |
Instruction | Statements that are out of order due to optimization are preceded by “*>”. | |
|
|
How ALAT Metrics Are Obtained
HP Caliper obtains ALAT metrics from the processor's performance monitoring unit (PMU).
Exact counts are obtained from the PMU's set of performance monitor configuration (PMC)/performance monitor data (PMD) register pairs. Sampled ALAT metrics are obtained from the PMU's data event address register
HP Caliper takes samples every Nth recorded ALAT miss, where N is defined in the alat measurement configuration file in the HP Caliper home directory config subdirectory. At each sample point, HP Caliper records the instruction that resulted in an ALAT miss. You can override the value in the measurement configuration file by using the
More frequent sampling increases HP Caliper's perturbation of your application. In particular, taking a sample could cause some of the ALAT content to be replaced. If so, the following chk.a/ld.c instructions are more likely to fail, making the resulting data of limited value.
branch Measurement Report Description
With the branch measurement, produced by the branch measurement configuration file, HP Caliper measures and reports two levels of information:
•Exact counts of branch prediction metrics summed across the entire run of an application
•Sampled branch prediction metrics that are associated with particular locations in the application
The report shows measured data by thread, load module, function, statement, instruction bundle, and instruction.
branch Measurement Report Description 171