FLAG_wasm_dynamic_tiering is still off by default. When enabled,
it now uses the technique previously behind --new-wasm-dynamic-tiering.
Bug: v8:12281
Change-Id: I365c2c066e62418cd6abc7830f95d1fe0f950e33
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3275570
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77883}
This is a reland of 79d63a5ef3. Some fixes
landed already, and two tests need to be skipped now (one with a tracking
bug).
Original change's description:
> [wasm] Remove all implications from --predictable
>
> In predictable mode, we want to execute the same code as otherwise,
> modulo timing. Hence remove any implications which change behaviour
> (like tier-up or asynchronous compilation).
> Note that --predictable is a debugging flag, so the configurations does
> not need to "make sense" in production.
>
> R=ahaas@chromium.org
>
> Bug: v8:11848
> Change-Id: If74fbacadeb087d977922c41f33fd18738b50ded
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2940898
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#74973}
Bug: v8:11848
Change-Id: I3564e4351d6545bb9643d1ae44722eb2606b8961
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2944936
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75009}
In order to improve our tiering strategy, it is a good idea to start
by tiering up functions that will be used the most, as this is done in
most JavaScript engines.
To decide which function requires tiering, we use as a basic strategy
to define its compilation priority to 'func_size * number_of_calls',
this roughly approximates the time we spend in the function.
To handle prioritization, it seemed that using a concurrent
priority queue similar to BigUnits was causing concurrencies issues.
I then decided to use different priority queues for each worker thread.
R=clemensb@chromium.orgCC=thibaudm@chromium.org
Bug: v8:10728
Change-Id: I6f314468549000b2a9b51d3d470f04a0cb997879
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2367859
Commit-Queue: Arnaud Robin <arobin@google.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69585}
On desktop systems, we use a very basic tiering strategy: Everything is
initially compiled with Liftoff, and once that is done, the module can
start being used. Concurrently to the execution, we re-compile all code
with TurboFan, and hot-swap each function once TurboFan finishes.
We should start using a more dynamic strategy where each function is
tiered-up when judged necessary. This change will then tier-up each
liftoff function once it has been called 5 times.
I then added a counter in the native module, that is updated directly
from Liftoff code, and a runtime call is then made when the counter
reaches the goal.
R=clemensb@chromium.org
CC=thibaudm@chromium.org
Bug: v8:10728
Change-Id: I8dc2b02fdff8d97781bb1cf496886594b3d7f644
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2306803
Commit-Queue: Arnaud Robin <arobin@google.com>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68971}
