Subject: RE: Performance Problem: malloc() is calling madvise()
To: None <>
From: Bill Dorsey <>
List: current-users
Date: 05/19/2000 13:20:44

The performance figures I gave earlier with my C++ application
may not have been realistic as I ran it on a very small
problem set (it takes a long time to run on the full problem
set).  I reconfigured it to run on the full problem set but
set it to stop after completing only 1/32 of the work.  This
allowed me to run it in a reasonable amount of time but get
realistic memory usage from it.  Below is a table listing the
performance figures I get with from 1.4.2_Alpha and
from 1.4Y (on a DEC Personal Workstation):

Library         Options                 Run time      MALLOC_OPTIONS=""       38.229u 61.542s      MALLOC_OPTIONS="h"      32.475u  0.048s      MALLOC_OPTIONS=""       29.716u  0.043s

The changes in (after setting MALLOC_OPTIONS to "h")
still impact my performance by -9% or so.  I realize that this
may be offset by increased performance in other applications,
so this could be a non-issue.  Still, it would be nice to know
that this was done cogently and not as the by-product of some
other change.

Bill Dorsey