touch-packages team mailing list archive

[Daniel van Vugt <daniel.van.vugt@xxxxxxxxxxxxx>]

** Summary changed:

- [android] Mir spends 12%+ CPU time in get_hooked_symbol (libhybris-common) comparing strings
+ [performance] Mir spends 12%+ CPU time in get_hooked_symbol (libhybris-common) comparing strings

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https://bugs.launchpad.net/bugs/1343198

Title:
  [performance] Mir spends 12%+ CPU time in get_hooked_symbol
  (libhybris-common) comparing strings

Status in Mir:
  In Progress
Status in “libhybris” package in Ubuntu:
  In Progress

Bug description:
  On the N4, Mir spends 12%+ CPU time in get_hooked_symbol (libhybris-
  common). Actually callgrind can't decide; it's somewhere between 12%
  and 46000% ;)

  So it's big. Looking at the hybris code, there's a rather large
  bottleneck that's obvious: get_hooked_symbol does a linear search
  (many times) of a large list of strings using strcmp alone. That's why
  22132 calls to get_hooked_symbol are yielding over 5 million calls to
  strcmp.

  Upstream hybris appears to have been modified to use a cache/hashing
  instead of the ugly linear search we have.

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