[Wine] Speed/latency issues for development in a Wine environment

[Alan W. Irwin]

I am an experienced Linux developer but a Wine newbie.  Recently I have been
exploring the possibility of using CMake-2.8.1 and MinGW-4.5.0 in a
Wine-1.1.42 environment (the backported Debian Lenny packages from WineHQ)
to check that CMake-based build systems I use for various software projects
work properly for that Windows platform.  I am collecting notes for a wiki
entry I am planning to write about using this platform for software
development if anybody else here is interested.

My initial experiences have been promising for this platform.  For example,
I have been able to build CMake itself as well as build and test PLplot.

However, one issue that is of concern is the builds are extremely slow on
Wine compared to Linux.

Here are some comparisons for components of CMake builds done in an
initially empty build tree.

Wine I.
wine at raven> time wine cmake -G "MinGW Makefiles" \
"-DCMAKE_INSTALL_PREFIX=z:/home/wine/cmake/install1" \
z:/home/software/cmake/cmake-2.8.1_patched/ >& cmake.out

real    14m17.124s
user    0m16.233s
sys     0m6.320s

That real time is a factor of ~40 (!) longer than the sum of user and sys
time which implies wine is spending most of its time in a wait state for
this work load with no cpu activity at all.  I frankly don't believe those
numbers for user and sys and therefore don't necessarily believe this
explanation because the user and sys numbers are clearly unreliable for the
next experiment. However, for all experiments the real time is reliable from
my independent time measurements

Wine II.

wine at raven> time wine mingw32-make install >& make_install.out

real    20m13.421s
user    0m0.136s
sys     0m0.012s

For this workload the ratio between the "wait" time and total cpu time is 
a factor of 8000 (!)  But thse user and sys numbers are so tiny compared
to the corresponding Linux experiement that I don't trust them.  But
real time is reliable.

Wine III.

Here are the corresponding latency numbers (how long it takes make to
figure out that nothing has to be done by running this command right
after the previous one).

wine at raven> time wine mingw32-make install >& make_install.out1

real    1m39.018s
user    0m0.100s
sys     0m0.052s

By looking at make_install.out1 I confirmed that indeed nothing was done
other than to check dependencies (which normally involves running make a
fairly large number of times for CMake-based build systems).

Here are the corresponding timing numbers under Linux for the same three
experiments for an initially empty build tree and Linux versions of
CMake-2.8.1 and gcc-4.3.2 (for Debian Lenny).

Linux I.

wine at raven> time cmake -G "Unix Makefiles" \
"-DCMAKE_INSTALL_PREFIX=/home/wine/cmake/install_linux" \
/home/software/cmake/cmake-2.8.1_patched/ >& cmake.out

real    0m34.015s
user    0m18.513s
sys     0m6.100s

This user+sys time is actually reasonably similar to the equivalent for Wine
I, but that may just be a coincidence.  The reliable fact to draw from this
is the overall real time is a factor of 25 (!) faster or ~13 minutes (!)
faster than the Wine I equivalent.  Why?

Linux II.

wine at raven> time make install >& make_install.out

real    2m12.805s
user    1m56.607s
sys     0m13.665s

Here user+sys add up closely to real time so there are virtually no times
in this Linux build case where the cpu is idle.  The real time
is a factor of 9 (!) faster or 18 minutes (!) faster than
the Wine II case.

Linux III.

wine at raven> time make install >& make_install.out1

real    0m0.869s
user    0m0.592s
sys     0m0.272s

This "latency" time required to figure out dependencies and decide nothing
needs to be done (confirmed by looking at make_install.out1) is a factor
(in real time) of ~110 faster or 1m34s faster than the Wine III case.

One Wine slowness factor that affects all these results is that wine has a
long start-up latency for every task that is run by a command such as cmake
or make in the wine environment. Indeed when I did timing experiments for
simple commands such as "wine cmake --version" or "wine gcc --version" that
are normally instantaneous on Linux, there seemed to always be a start-up
latency near 0.25 seconds which was not from the wine command itself (since
commands like "wine lxx" returned much faster than 0.25 seconds saying the
lxx.exe command could not be found).  A CMake build and install (the work that
occurs for the Wine and Linux II timing experiments) requires roughly 3000
commands to complete.  So the Wine startup latency accounts for roughly 12
minutes of the measured 18 minute discrepancy between Wine II and Linux II,
and considering the roughness of that 12-minute estimate it is reasonable to
ascribe all the difference to Wine startup latency.  So let's also take
that as a working hypothesis to explain the Wine I versus Linux I
discrepancy of ~13 minutes (where I am not sure how many commands are run)
and the Wine III versus Linux III discrepancy of 1m38s (where I know
many fewer commands were run than in the Wine II and Linux II cases).

Given the known Wine startup latency for simple commands and the possibility
that all these timing comparsion results for the same build on Linux and
Wine can be explained by that, what can I do to reduce that latency? Note,
all Wine results above were done with "timeserver -p" run beforehand. Also,
the environment variable controlling Wine debugging was set to
WINDEBUG='-all" (as suggested in a web article I read) to eliminate that
particular source of latency.

If some Wine developer suggests rebuilding Wine with a different
configuration than that used in the WineHQ Debian Lenny packages for 1.1.42
I would be happy to try that.  I would also be happy to test any further
changes they would like to make to the Wine source code to reduce startup
latency. For example, if Wine establishes a useless GUI environment each
time a command such as gcc is run under Wine, I would be happy to test a
run-time option to eliminate that.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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Linux-powered Science
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