On 17/07/2024 16:57, Jeroen Koekkoek wrote: Hi Jeroen,
That is indeed correct. At runtime the CPUID instruction is used to detect which extensions are offered and it chooses based on that. When compiling on x86_64 with SSE4.2 and AVX2 enabled, the binary will actually contain 3 parsers, the most optimal one is used at runtime.
Thanks for this clarification. NSD doesn't log this info when starting, and "nsd -v" also doesn't reveal which parser it has chosen. I think such information will be useful to both users and developers, especially when trying to debug an issue. Do you think you could add this to the output of "nsd -v" (something like which parsers have been compiled, and which one is being chosen)?
So a question: as a packager and distributor, do I need to build on a processor that has both SSE4.2 and AVX2 instructions enabled? And if one or both of these are not enabled, will the resulting build contain fewer parsers?
Optimized versions can be disabled with --disable-westmere (SSE4.2) and --disable-haswell (AVX2) if desired btw.
Thanks for providing these options. But it would help users to know the effects of enabling/disabling these options, so that they can make an informed choice.
Another question: if a user has a binary containing all three parsers, and wants to disable one or more of them at run-time, how is the user supposed to do this?
Actually, I just went to look at doc/README, which has notes on how to compile NSD, but not all the enable/disable options are fully documented, so a user cannot make informed choices about whether to enable/disable certain features in their builds. I think I'll open a separate issue about this.
Regards, Anand _______________________________________________ nsd-users mailing list nsd-users@lists.nlnetlabs.nl https://lists.nlnetlabs.nl/mailman/listinfo/nsd-users
