tcpdump mailing list archives
Re: Which is fastest a 32 or 64 bit pcaplib on a 64 bit OS?
From: Guy Harris <guy () alum mit edu>
Date: Tue, 18 Apr 2017 11:22:17 -0700
On Apr 11, 2017, at 10:40 AM, Joseph Freemaker <joseph_freemaker () yahoo com> wrote:
On a 64 bit OS does a 64 bit compiled libpcap provide better performance than a 32 bit compiled libpcap?
I don't know whether anybody's measured it on any particular platforms. A 64-bit libpcap would have bigger pointers and size_t variables, which might increase its memory and cache footprint, possibly slowing it down. However, there might also be some extra overhead due to translation of 32-bit pointer and size arguments in system calls. And, if the platform happens to be x86 or ARM, 32-bit code has fewer registers available than 64-bit code (unless the compiler and OS support a "64-bit instruction set but with 32-bit pointers" mode; I think there's something like that for Linux on x86, for example). So, without a measurement, I'm not going to try to guess which will offer better performance. If your later question about AIX indicates that you're running AIX 6, that means it's on a Power ISA machine, so the "fewer registers can slow down 32-bit code" part won't apply. _______________________________________________ tcpdump-workers mailing list tcpdump-workers () lists tcpdump org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Current thread:
- Which is fastest a 32 or 64 bit pcaplib on a 64 bit OS? Joseph Freemaker (Apr 18)
- Re: Which is fastest a 32 or 64 bit pcaplib on a 64 bit OS? Guy Harris (Apr 18)