From: Satheesh Rajendran <sathn...@linux.vnet.ibm.com>
Certain systems would have sparse/discontinguous
numa nodes.
perf bench numa doesnt work well on such nodes.
1. It shows wrong values.
2. It can hang.
3. It can show redundant information for non-existant nodes.
#numactl -H
available: 2 nodes (0,8)
node 0 cpus: 0 1 2 3 4 5 6 7
node 0 size: 61352 MB
node 0 free: 57168 MB
node 8 cpus: 8 9 10 11 12 13 14 15
node 8 size: 65416 MB
node 8 free: 36593 MB
node distances:
node 0 8
0: 10 40
8: 40 10
Scenario 1:
Before Fix:
# perf bench numa mem --no-data_rand_walk -p 2 -t 20 -G 0 -P 3072 -T 0 -l 50
-c -s 1000
...
...
# 40 tasks will execute (on 9 nodes, 16 CPUs): ----> Wrong number of nodes
...
# 2.0% [0.2 mins] 1/1 0/0 0/0 0/0 0/0 0/0 0/0 0/0 4/1 [
4/2 ] l: 0-0 ( 0) ----> Shows info on non-existant nodes.
After Fix:
# ./perf bench numa mem --no-data_rand_walk -p 2 -t 20 -G 0 -P 3072 -T 0 -l 50
-c -s 1000
...
...
# 40 tasks will execute (on 2 nodes, 16 CPUs):
...
# 2.0% [0.2 mins] 9/1 0/0 [ 9/1 ] l: 0-0 ( 0)
# 4.0% [0.4 mins] 21/2 19/1 [ 2/3 ] l: 0-1 ( 1) {1-2}
Scenario 2:
Before Fix:
# perf bench numa all
# Running numa/mem benchmark...
....
...
# Running RAM-bw-remote, "perf bench numa mem -p 1 -t 1 -P 1024 -C 0 -M 1 -s
20 -zZq --thp 1 --no-data_rand_walk"
perf: bench/numa.c:306: bind_to_memnode: Assertion `!(ret)' failed.
------------> Got hung
After Fix:
# ./perf bench numa all
# Running numa/mem benchmark...
....
...
# Running RAM-bw-remote, "perf bench numa mem -p 1 -t 1 -P 1024 -C 0 -M 1 -s
20 -zZq --thp 1 --no-data_rand_walk"
# NOTE: ignoring bind NODEs starting at NODE#1
# NOTE: 0 tasks mem-bound, 1 tasks unbound
20.017 secs slowest (max) thread-runtime
20.000 secs fastest (min) thread-runtime
20.006 secs average thread-runtime
0.043 % difference between max/avg runtime
413.794 GB data processed, per thread
413.794 GB data processed, total
0.048 nsecs/byte/thread runtime
20.672 GB/sec/thread speed
20.672 GB/sec total speed
Changes in v2:
Fixed review comments for function names and alloc failure handle
Satheesh Rajendran (2):
perf/bench/numa: Add functions to detect sparse numa nodes
perf/bench/numa: Handle discontiguous/sparse numa nodes
tools/perf/bench/numa.c | 52 ++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 45 insertions(+), 7 deletions(-)
--
2.7.4
