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b8a1962d17
Adding stat-cpi.py as an example of how to do stat scripting.
It computes the CPI metrics from cycles and instructions events.
The CPI is based performance metric showing the Cycles Per Instructions
ratio, which helps to identify cycles-hungry code.
Following stat record/report/script combinations could be used:
- get CPI for given workload
$ perf stat -e cycles,instructions record ls
SNIP
Performance counter stats for 'ls':
2,904,431 cycles
3,346,878 instructions # 1.15 insns per cycle
0.001782686 seconds time elapsed
$ perf script -s ./scripts/python/stat-cpi.py
0.001783: cpu -1, thread -1 -> cpi 0.867803 (2904431/3346878)
$ perf stat -e cycles,instructions record ls | perf script -s ./scripts/python/stat-cpi.py
SNIP
0.001730: cpu -1, thread -1 -> cpi 0.869026 (2928292/3369627)
- get CPI systemwide:
$ perf stat -e cycles,instructions -a -I 1000 record sleep 3
# time counts unit events
1.000158618 594,274,711 cycles (100.00%)
1.000158618 441,898,250 instructions
2.000350973 567,649,705 cycles (100.00%)
2.000350973 432,669,206 instructions
3.000559210 561,940,430 cycles (100.00%)
3.000559210 420,403,465 instructions
3.000670798 780,105 cycles (100.00%)
3.000670798 326,516 instructions
$ perf script -s ./scripts/python/stat-cpi.py
1.000159: cpu -1, thread -1 -> cpi 1.344823 (594274711/441898250)
2.000351: cpu -1, thread -1 -> cpi 1.311972 (567649705/432669206)
3.000559: cpu -1, thread -1 -> cpi 1.336669 (561940430/420403465)
3.000671: cpu -1, thread -1 -> cpi 2.389178 (780105/326516)
$ perf stat -e cycles,instructions -a -I 1000 record sleep 3 | perf script -s ./scripts/python/stat-cpi.py
1.000202: cpu -1, thread -1 -> cpi 1.035091 (940778881/908885530)
2.000392: cpu -1, thread -1 -> cpi 1.442600 (627493992/434974455)
3.000545: cpu -1, thread -1 -> cpi 1.353612 (741463930/547766890)
3.000622: cpu -1, thread -1 -> cpi 2.642110 (784083/296764)
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1452077397-31958-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
#!/usr/bin/env python
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data = {}
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times = []
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threads = []
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cpus = []
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def get_key(time, event, cpu, thread):
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return "%d-%s-%d-%d" % (time, event, cpu, thread)
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def store_key(time, cpu, thread):
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if (time not in times):
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times.append(time)
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if (cpu not in cpus):
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cpus.append(cpu)
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if (thread not in threads):
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threads.append(thread)
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def store(time, event, cpu, thread, val, ena, run):
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#print "event %s cpu %d, thread %d, time %d, val %d, ena %d, run %d" % \
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# (event, cpu, thread, time, val, ena, run)
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store_key(time, cpu, thread)
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key = get_key(time, event, cpu, thread)
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data[key] = [ val, ena, run]
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def get(time, event, cpu, thread):
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key = get_key(time, event, cpu, thread)
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return data[key][0]
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def stat__cycles_k(cpu, thread, time, val, ena, run):
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store(time, "cycles", cpu, thread, val, ena, run);
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def stat__instructions_k(cpu, thread, time, val, ena, run):
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store(time, "instructions", cpu, thread, val, ena, run);
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def stat__cycles_u(cpu, thread, time, val, ena, run):
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store(time, "cycles", cpu, thread, val, ena, run);
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def stat__instructions_u(cpu, thread, time, val, ena, run):
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store(time, "instructions", cpu, thread, val, ena, run);
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def stat__cycles(cpu, thread, time, val, ena, run):
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store(time, "cycles", cpu, thread, val, ena, run);
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def stat__instructions(cpu, thread, time, val, ena, run):
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store(time, "instructions", cpu, thread, val, ena, run);
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def stat__interval(time):
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for cpu in cpus:
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for thread in threads:
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cyc = get(time, "cycles", cpu, thread)
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ins = get(time, "instructions", cpu, thread)
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cpi = 0
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if ins != 0:
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cpi = cyc/float(ins)
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print "%15f: cpu %d, thread %d -> cpi %f (%d/%d)" % (time/(float(1000000000)), cpu, thread, cpi, cyc, ins)
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def trace_end():
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pass
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# XXX trace_end callback could be used as an alternative place
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# to compute same values as in the script above:
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#
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# for time in times:
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# for cpu in cpus:
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# for thread in threads:
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# cyc = get(time, "cycles", cpu, thread)
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# ins = get(time, "instructions", cpu, thread)
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#
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# if ins != 0:
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# cpi = cyc/float(ins)
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#
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# print "time %.9f, cpu %d, thread %d -> cpi %f" % (time/(float(1000000000)), cpu, thread, cpi)
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