On Tue, Aug 17, 2010 at 7:59 AM, Johan Hartzenberg <jhart...@gmail.com> wrote: > If however your application use the features of 64-bit programs then the > advantages can be more than these overheads. For the most part this means > programs that require access to more than 4 GB of data in RAM.
A lot of applications get a boost in performance in 64-bit because they get 16 general purpose registers (vs. 8 in 32-bit mode), but this is true for x64 vs x86 only. So profile the app and find out where it is spending most time in is the best starting point. Rayson > > Cheers, > _Johan > > On Tue, Aug 17, 2010 at 4:23 AM, Jim Mauro <james.ma...@oracle.com> wrote: >> >> Typically such performance disparities are due to >> changes in the memory footprint with the 64-bit code, >> and resulting cache miss rates being higher with the >> 64-bit code than the 32-bit code. >> >> You need to use the Studio tools to profile the code, >> and/or cputrack to measure cache hit rates. >> >> Thanks, >> /jim >> >> >> On Aug 16, 2010, at 9:58 PM, Kishore Kumar Pusukuri wrote: >> >> > Hi, >> > I am surprised with the performances of some 64-bit multi-threaded >> > applications on my AMD Opteron machine. For most of the applications, the >> > performance of 32-bit version is almost same as the performance of 64-bit >> > version. However, for a couple of applications, 32-bit versions provide >> > better performance (running-time is around 76 secs) than 64-bit (running >> > time is around 96 secs). Could anyone help me to find the reason behind >> > this, please? >> > >> > >> > $ldd program-64 (64-bit version) >> > libpthread.so.1 => /lib/64/libpthread.so.1 >> > libstdc++.so.6 => /usr/lib/64/libstdc++.so.6 >> > libm.so.2 => /lib/64/libm.so.2 >> > libgcc_s.so.1 => /usr/lib/64/libgcc_s.so.1 >> > libc.so.1 => /lib/64/libc.so.1 >> > >> > $ ldd program-32 (32-bit version) >> > libpthread.so.1 => /lib/libpthread.so.1 >> > libstdc++.so.6 => /usr/lib/libstdc++.so.6 >> > libm.so.2 => /lib/libm.so.2 >> > libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 >> > libc.so.1 => /lib/libc.so.1 >> > -- >> > This message posted from opensolaris.org >> > _______________________________________________ >> > perf-discuss mailing list >> > perf-discuss@opensolaris.org >> >> _______________________________________________ >> perf-discuss mailing list >> perf-discuss@opensolaris.org > > > > -- > Any sufficiently advanced technology is indistinguishable from magic. > Arthur C. Clarke > > My blog: http://initialprogramload.blogspot.com > > _______________________________________________ > perf-discuss mailing list > perf-discuss@opensolaris.org > _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
