Serious performance problems (malloc related?)

[Gerrit P. Haase]

Vaclav Haisman wrote:

> On Sat, 28 May 2005, Gerrit P. Haase wrote:
> 
> 
>>Andy Ross wrote:
>>
>>>But as I noted in my original post: It's not waiting on the disk
>>>reads.  Comment out the split() call and watch the delays disappear.
>>>Raw I/O speed in cygwin is comparable to mingw or MSVC.  The overhead
>>>is due, somehow, to activity within/under split().  Other than
>>>allocation, that function doesn't do any meaningful library
>>>interaction that I can see (although Vaclav's suggestion about
>>>exception handling is a very good one...).
>>
>>Can you port the testcase you provided to C to see if it makes a
>>difference, please?
> 
> 
> Or maybe at least try -fno-exceptions...

This speeds up things about 20% for me:

$ g++ -fno-exceptions -c cygspd.cc -o cygspd.o

$ g++ -fno-exceptions -o cygspd cygspd.o

$ time ./cygspd cygspd.dat

real    0m39.892s
user    0m38.405s
sys     0m0.155s

instead of compiling without the flag:

$ time ./cygspd cygspd.dat

real    0m51.071s
user    0m50.108s
sys     0m0.046s

Using optimization speeds up things again:

$ g++ -fno-exceptions -O7 -c cygspd.cc -o cygspd.o

$ g++ -fno-exceptions -o cygspd cygspd.o

$ time ./cygspd cygspd.dat

real    0m28.024s
user    0m27.030s
sys     0m0.061s


Gerrit
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