On 02.07.2019 17:37, Kevin Wolf wrote: > Am 02.07.2019 um 14:49 hat Denis Plotnikov geschrieben: >> On 28.06.2019 14:57, Kevin Wolf wrote: >>> Am 28.05.2019 um 16:37 hat Denis Plotnikov geschrieben: >>>> diff --git a/configure b/configure >>>> index 1c563a7027..c90716189c 100755 >>>> --- a/configure >>>> +++ b/configure >>>> @@ -433,6 +433,7 @@ opengl_dmabuf="no" >>>> cpuid_h="no" >>>> avx2_opt="" >>>> zlib="yes" >>>> +zstd="yes" >>> >>> This should be zstd="" so that a missing library will automatically >>> disable it instead of producing an error. (Building QEMU without zlib is >>> impossible, but building it without ZSTD should work.) >> But if we add zstd for clusters compression we have to build with zstd >> each time. If we want to chose whether we want to build zstd we need to >> enclose all zstd related code with "ifdef"-s. >> I don't think it's good because we can end up with mess of version >> supporting and not supporting zstd compression. > > Yes, we'll need ifdefs. Or we could do it like the dmg compression > formats, a spearate source file for zstd that is compiled conditionally. > > Anyway, I don't think making zstd a hard dependency for qemu is > acceptable. > >> Another point is what the benefit of building qemu without zstd support >> is since it's available and provides better performance than zlib (i.e. >> the replacement for zlib) ? > > Is it available in all relevant distros and even non-Linux platforms > that we support? > > Another reason for wanting to compile it out even when it is available > is startup time. Each shared library to be loaded takes some time, and > there are use cases where you want a minimal guest to boot up really > fast. > > Kevin
Sounds like important points. Thanks for the explanation! > -- Best, Denis
