• Benedikt Meurer's avatar
    [inspector] Cache StackFrames by script, line and column number. · e60dc99e
    Benedikt Meurer authored
    This introduces a stack frame cache on the V8Debugger level, which
    de-duplicates StackFrame instances based on their scriptId, line and
    column number.
    
    This greatly reduces the memory pressure when debugging huge Web
    applications that have a lot of async activity (and potentially
    have scripts with huge URLs). This is guided by the observation
    that even in huge applications, there are only a very limited
    number of call sites that initiate async activity and hence we
    only have a limited number of distinct StackFrames to worry
    about (despite having to maintain a large number of async stack
    traces overall).
    
    As a nice side effect, this CL also greatly reduces the negative
    performance impact of collecting async stack traces in these
    huge applications.
    
    Generally speaking this is mostly duct tape however, and we might
    want to follow up with changes to make capturing (and storing)
    stack frames even cheaper.
    
    Fixed: chromium:1268436
    Change-Id: Ib212b3c97dce2bb7ca47d5875d45cf20b9b97afe
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3272577
    Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
    Reviewed-by: 's avatarSimon Zünd <szuend@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#77835}
    e60dc99e
v8-debugger.cc 45.1 KB