64-bit Solaris slower than 32-bit?

[HaloJones]

I have one instance of df running (as a test only of course) on a Sunfire 6800. The 32-bit version was producing around 50K per day but after replacing with the 64-bit it isnow producing 44K per day! Does this match with other experience or is there something wrong?

[Brian the Fist]

Could bery well be. No one says 64-bit is faster, especially for mostly 32-bit code, just bigger bulkier pointers.

[shifted]

Originally posted by Brian the Fist
Could bery well be. No one says 64-bit is faster, especially for mostly 32-bit code, just bigger bulkier pointers.

Generally, any given code that doesn't require 64 bits will be slower using 64 bits. The bulkier pointers are the cause, because that's more info moving around that only accomplishes the same thing. On a related note, having a wider data-path in the cpu (more bits for data versus more bits for addressing) makes a significant difference... which is why the athlon series is faster than the p4's at a given mhz (at least before SSE). The nice thing about 64 bits is the ability to address more than 4 GB of storage (without paging).