On 5/25/26 3:41 PM, Wentao Guan wrote: >> On 5/25/26 10:02 AM, Wentao Guan wrote: >>>> Additionally, many distributions already switched to gendwarfksyms last >>>> year. Unless someone provides a good reason to keep genksyms around, >>>> I expect it will be deprecated soon and eventually removed. It would be >>>> more valuable to show whether the same optimization is worthwhile for >>>> gendwarfksyms. >>> I see gendwarfksyms use crc32 from <zlib.h>, which from zlib1g-dev and >>> zlib1g. >> >> Ah, I forgot about this, so gendwarfksyms should already be well >> optimized. I think that is the most important thing. > > Which way do you prefer? There are two ways now: > 1. this work, > 2. import zlib like gendwarfksyms and remove the huge crctab, > but need make sure any arch do not cause performance regression? > (Assert the user libs precompile with +crc32 is right?) > I do some early tests show that: > 1) zlib in x86 fast than genksym software > 2) zlib in arm64 debian precompile slow than genksym software(crc32 not in > armv8) > 3) zlib in arm64 recompile with +crc32 same speed with genksyms hardware
I think it would be useful to first have more data showing that the CRC calculation in genksyms is a hot path and contributes significantly to the overall kernel build time. -- Thanks, Petr
