I ported an application from QNX4 to Windows XP. The application accepting
incomming data via TCP/IP, perform data analysis and then spit the result
back via TCP/IP.
I was very curious to see how the Intel C compiler would compare with
Watcom. I have turn every optimisation on and tried bunch of diffdrent
combinaison of optimisation flag, I looked at the assembly code and the
Intel compiler threw a bunch of SSE instruction ( I had high hope this would
make a big difference).
The best the Intel compiler could do is match Watcom.,whichI though was
worth a post , the Intel executalbe is 33% bigger
That being said, the code was run on AMD64, maybe it could run faster on P4.
The source code had gone through many years of hand crafted optimisation
which i guess help Watcom.
The code was hacked so that it would accept to run on AMD64 without having
to generate a specific code path for both P4 “Genuine Intel” and non
“|Genuine Intel”, maybe that’s negatively affected the performance on AMD64.