Re: Performance problem with gcc 4.9.2-3 on 64 bit
Marco Atzeri wrote: >On 2/27/2015 5:49 PM, Bengt Larsson wrote: >> Below are two benchmarks that explore maximum floating point >> performance. loopm6 is double precision floating point and loopm6fp is >> parallell single-precision. They are manually unrolled multiply-add >> loops. >> >> I used to reach 2.8 and 11 GFlops on these. Now I only get >> 2 and 6. >> >> If you explore the inner loop with gcc -O2 -S you can see that it seems >> to use few registers. >> >> If you run them, there is a parameter expected. I use 3 - 5. >> >> gcc 4.9.2-3 on 64-bit. I use gcc -O2. >> > >May be >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53967 I think that was longer ago. On the version before 4.9.* on Cygwin I got full speed. -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Re: Performance problem with gcc 4.9.2-3 on 64 bit
On 2/27/2015 5:49 PM, Bengt Larsson wrote: Below are two benchmarks that explore maximum floating point performance. loopm6 is double precision floating point and loopm6fp is parallell single-precision. They are manually unrolled multiply-add loops. I used to reach 2.8 and 11 GFlops on these. Now I only get 2 and 6. If you explore the inner loop with gcc -O2 -S you can see that it seems to use few registers. If you run them, there is a parameter expected. I use 3 - 5. gcc 4.9.2-3 on 64-bit. I use gcc -O2. May be https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53967 -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Performance problem with gcc 4.9.2-3 on 64 bit
Below are two benchmarks that explore maximum floating point performance. loopm6 is double precision floating point and loopm6fp is parallell single-precision. They are manually unrolled multiply-add loops. I used to reach 2.8 and 11 GFlops on these. Now I only get 2 and 6. If you explore the inner loop with gcc -O2 -S you can see that it seems to use few registers. If you run them, there is a parameter expected. I use 3 - 5. gcc 4.9.2-3 on 64-bit. I use gcc -O2. loopm6.c Description: Binary data loopm6fp.c Description: Binary data timers.h Description: Binary data -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
