Multiple regions of interest

Application source code changes

Include the header file which defines Sniper's magic instructions. Make sure to compile using -I $SNIPER_ROOT/include so sim_api.h can be found.

#include <sim_api.h>

Add Magic markers around regions of interest. Arguments to SimMarker(a, b) can be any two integers, but by convention, a=1 for start, a=2 for stop, while b is the region identifier.

(setup code)
 
SimMarker(1, 1001);
(region 1001 code)
SimMarker(2, 1001);
 
(uninteresting code)
 
SimMarker(1, 2345);
(region 2345 code)
SimMarker(2, 2345);
 
(fini code)

Or for an iteration-based benchmark:

for(int iter = 0; iter < 10; ++iter)
{
    SimMarker(1, iter);
    (loop body)
    SimMarker(2, iter);
}

Running a single selected region in Sniper

The roi-iter.py script can select the region of interest by watching for SimMarker calls, with optional cache warmup

run-sniper -c CONFIG --roi-script [--no-cache-warming] -s roi-iter:A:B:C -- benchmark args ...

With:

• A = region ID of when to start cache warmup
• B = region ID of first region to run in detailed mode
• C = region ID of last region to run in detailed mode
• --no-cache-warming is used to disable cache warmup in code before region A

Examples:

Run a single region with ID 42 in detailed mode, with all code before it in cache-only:

run-sniper -c CONFIG --roi-script -s roi-iter::42:42

Run benchmark iterations 100..110 in cache-only, 111-115 in detailed mode, fast-forward up to region 100 and after region 115:

run-sniper -c CONFIG --roi-script --no-cache-warming -s roi-iter:100:111:115

Selecting regions after simulating everything

Simulate the complete application (or everything inside the usual SimRoiBegin/SimRoiEnd markers), and store statistics snapshots whenever encountering a SimMarker;

run-sniper -c CONFIG [--roi] -s markers:stats

Select the region between two markers for processing using --partial=region-begin:region-end

# List all available markers
$ ./tools/dumpstats.py -l
start, roi-begin, marker-1-1001, marker-2-1001, marker-1-2345, marker-2-2345, roi-end, stop
$ tools/cpistack.py --partial=marker-1-1001:marker-2-1001
(CPI stack for region 1001)
$ tools/gen_simout.py --partial=marker-1-2345:marker-2-2345
(sim.out for region 2345)