| commit | 6d1e7bc337d1a075d8841568614653b9da3e000a | [log] [tgz] |
|---|---|---|
| author | Srikrishna Iyer <sriyer@google.com> | Sat Aug 20 09:43:13 2022 -0700 |
| committer | Srikrishna Iyer <46467186+sriyerg@users.noreply.github.com> | Fri Aug 26 09:31:33 2022 -0700 |
| tree | 02e96b957f70401c979fb478fae6e2a452a3a978 | |
| parent | a899593139af962e52dd1c4b74b7edfbe2ed6bb1 [diff] |
[sw] Enhance rand_testutils to set seed value This commit uses the on-device entropy source to fetch a random value to set the initial seed value from the on-device entropy source. for the LFSR implemented in SW. The SW LFSR (PRNG) offers better runtime performance than always seeking random data from the on-device entropy source. This enables SW randomization across all simulation platforms. The original goal for DV was to use a static volatile const symbol to set the seed value, that can be overridden from the testbench. However, after experimentation, this was found to offer only about 3-7% runtime improvement. So, we will use the first method for all sim platforms. The rand_testutils provides a `rand_testutils_rng_t` type, which provides knobs and maintains an PRNG LFSR instance. It provides an LFSR reseed frequency which instructs the testutil to refresh the LFSR with a new seed after every N PRNG operations. In addition, it provides the ability to set the entropy fetch timeout in microseconds, and the PRNG LFSR polynomial coefficient, which are set to defaults upon initialization. They can be modified if the user wishes to. Signed-off-by: Srikrishna Iyer <sriyer@google.com>
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