Revert "RandUtil: Add Mersene Twister Enginer to thread's local storage to avoid"
This reverts commit ac6125e471ac4ab9dbca3a43e68c1892b9ab71cc.
Reason for revert: This change completely broke ChromeDriver for users
who run multiple instances of ChromeDriver. The seed for the new
random number generator can easily lead to same seed used by multiple
processes.
Original change's description:
> RandUtil: Add Mersene Twister Enginer to thread's local storage to avoid
> the overhead associated with seeding the generator.
>
> One can do ~18 M (~26 M) calls per second when using
> unifom_int_distribution on top of Mersene engine versus <1M (~ 8M) calls
> per second when using the current implementation on POSIX and Windows,
> respectively.
>
> Note that these figures are obtained when the generator is seeded once,
> otherwise the figure obtained for the suggested implementation would
> be <1M (this is for POSIX, we don't have the figure for windows).
> To that end, we use thread's local storage to seed the generator once.
>
> Change-Id: I628d2e0ab882a9703e52b4007d53fa5cf49d4d47
> Reviewed-on: https://chromium-review.googlesource.com/982115
> Commit-Queue: Farah Charab <farahcharab@chromium.org>
> Reviewed-by: Gabriel Charette <gab@chromium.org>
> Reviewed-by: Alexander Timin <altimin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#550496}
TBR=gab@chromium.org,altimin@chromium.org,farahcharab@chromium.org
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: I999423e955aa163c3863297ea9c81575a2ce8066
Reviewed-on: https://chromium-review.googlesource.com/1022250
Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552502}
CrOS-Libchrome-Original-Commit: 87cc25cd2fdcf5129bf9987e9d04d7d720b6577a
3 files changed