• Simon Zünd's avatar
    Reland "[array] Use random middle element to determine pivot during sorting" · 3896cdc2
    Simon Zünd authored
    This is a reland of 91bab558
    
    This CL contains two major changes w.r.t to the original CL:
    
    The random state is removed from the Smi root list and we pre-seed the RNG
    on each sort with the length of the array.
    
    To cut down on the length of the arguments list and to keep track of the
    random state across recursive calls, we move most of the sort arguments into
    a FixedArray and reload from the array for each recursion.
    
    Original change's description:
    > [array] Use random middle element to determine pivot during sorting
    >
    > This CL adds a "random state" to the Smi Root list and implements a
    > basic Linear congruential pseudo random number generator in Torque.
    >
    > The RNG is used to determine the pivot element for sorting. This will
    > prevent the worst cases for certain data layouts.
    >
    > Drive-by-fix: Make sorting of ranges and execution pauses for profviz
    > deterministic by adding a secondary sorting criteria.
    >
    > Bug: v8:7382
    > Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
    > Change-Id: Ieb871e98e74bdb803f821b0cd35d2f67ee0f2868
    > Reviewed-on: https://chromium-review.googlesource.com/1082193
    > Reviewed-by: Hannes Payer <hpayer@chromium.org>
    > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
    > Reviewed-by: Camillo Bruni <cbruni@chromium.org>
    > Commit-Queue: Simon Zünd <szuend@google.com>
    > Cr-Commit-Position: refs/heads/master@{#53524}
    
    Bug: v8:7382
    Change-Id: Ia7bef7ed1c0e904ffe43bc428e702f64f9c6a60b
    Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
    Reviewed-on: https://chromium-review.googlesource.com/1087888Reviewed-by: 's avatarCamillo Bruni <cbruni@chromium.org>
    Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
    Commit-Queue: Simon Zünd <szuend@google.com>
    Cr-Commit-Position: refs/heads/master@{#53583}
    3896cdc2
base.tq 19.4 KB