[tor-bugs] #20424 [Core Tor/Tor]: Remove --enable-openbsd-malloc (Tor maxes CPU when --enable-openbsd-malloc is used)

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#20424: Remove --enable-openbsd-malloc (Tor maxes CPU when --enable-openbsd-malloc
is used)
----------------------------+------------------------------------
 Reporter:  icanhasaccount  |          Owner:  (none)
     Type:  defect          |         Status:  needs_revision
 Priority:  Low             |      Milestone:  Tor: 0.3.4.x-final
Component:  Core Tor/Tor    |        Version:
 Severity:  Minor           |     Resolution:
 Keywords:                  |  Actual Points:
Parent ID:                  |         Points:  .2
 Reviewer:                  |        Sponsor:
----------------------------+------------------------------------
Changes (by Hello71):

 * cc: alex_y_xu@… (added)


Comment:

 proposal: remove tcmalloc and openbsd malloc, add jemalloc and enable by
 default on Linux if installed.

 pros compared to ptmalloc2:

 - moderately decreased CPU usage (#23777)
 - slightly decreased memory usage (fragmentation is much less bad in 0.3.2
 already, but jemalloc still does better by default)

 pros compared to openbsd malloc:

 - remove dead code
 - code path will be actually tested (unlike with openbsd malloc)
 - jemalloc is actually maintained by distributions and -ljemalloc is a
 standard method of overriding glibc. this way will continue to work,
 unlike just defining functions

 cons:

 - if always-on, adds an extra prerequisite. if used only when available,
 might cause more Linux-only bugs
 - glibc does slightly more runtime checks, but AFAIK these are almost
 entirely useless for security
 - might be fingerprintable? seems highly unlikely, and would also apply to
 other OSes

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20424#comment:19>
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