[dv regr tool] Use builtin for generating seeds
- The tool used octal dump [`od`] to pre-populate a list of 1000 random
numbers to be supplied as seeds to the tests
- Due to an unknown issue this ended up hanging on WDC machines
- This PR changes it to use python3 in-built library called 'secrets'
instead, which supposedly produces strong random numbers suitable for
crypto applications.
- Performance wise, the secrets lib takes 0.005s to generate 1000 random
numbers which is an order of magniture better than `od` which is a
system call that takes 0.097s. So this is an added plus.
Signed-off-by: Srikrishna Iyer <sriyer@google.com>
diff --git a/util/dvsim/Deploy.py b/util/dvsim/Deploy.py
index 2f57302..072a3d4 100644
--- a/util/dvsim/Deploy.py
+++ b/util/dvsim/Deploy.py
@@ -10,6 +10,7 @@
import pprint
import random
import re
+import secrets
import shlex
import sys
import time
@@ -483,13 +484,9 @@
@staticmethod
def get_seed():
if RunTest.seeds == []:
- try:
- # Pre-populate 1000 seeds at a time
- RunTest.seeds = run_cmd(
- "od -vAn -N4000 -tu < /dev/random | xargs").split()
- random.shuffle(RunTest.seeds)
- except Exception as e:
- log.error("%s. Failed to generate a list of 1000 random seeds",
- e)
- sys.exit(1)
+ # Py lib 'secrets' provides crypto quality strong random numbers.
+ for i in range(1000):
+ seed = secrets.token_bytes(4)
+ seed = int.from_bytes(seed, byteorder='little')
+ RunTest.seeds.append(seed)
return RunTest.seeds.pop(0)
