Nice work!
What exactly are you measuring, "make hotspot" or some other target?
If we can find a reasonable set of extra files for the windows pch that
restores all or most of the performance, that would of course be
preferable. I doubt we will find a significantly better selection on Mac
compared to Linux though.
/Erik
On 2018-11-02 07:00, Magnus Ihse Bursie wrote:
On 2018-11-02 12:14, Magnus Ihse Bursie wrote:
Caveats: I have only run this on my local linux build with the
default server JVM configuration. Other machines will have different
sweet spots. Other JVM variants/feature combinations will have
different sweet spots. And, most importantly, I have not tested this
at all on Windows. Nevertheless, I'm almost prepared to suggest a
patch that uses this selection of files if running on gcc, just as
is, because of the speed improvements I measured.
I've started running tests on other platforms. Unfortunately, I don't
have access to quite as powerful machines, so everything takes much
longer. For the moment, I've only tested my "BKM" (best known method)
from linux, to see if it works.
For xcode/macos I got:
real 4m21,528s
user 27m28,623s
sys 2m18,244s
hotspot with original pch
real 4m28,867s
user 29m10,685s
sys 2m14,456s
hotspot without pch
real 3m6,322s
user 19m3,000s
sys 1m41,252s
hotspot with new BKM pch
So obviously this is a nice improvement even here. I could probably
try around a bit and see if there is an even better fit with a
different selections of header files, but even without that, I'd say
this patch is by itself as good for clang as it is for gcc.
For windows I got:
real 6m39.035s
user 0m58.580s
sys 2m48.138s
hotspot with original pch
real 10m29.227s
user 1m6.909s
sys 2m24.108s
hotspot without pch
real 6m56.262s
user 0m57.563s
sys 2m27.514s
hotspot with new BKM pch
I'm not sure what's going on with the user time numbers here.
Presumably cygwin cannot get to the real Windows time data. What I can
see is the huge difference in wall clock time between PCH and no PCH.
I can also see that the new trimmed BKM list retains most of that
improvement, but is actually somewhat slower that the original list.
I'm currently rerunning with a larger set on Windows, to see if this
helps improve things. I can certainly live with a precompiled.hpp that
includes some additional files on Windows.
/Magnus
