Use binary serialization for communication to improve efficiency

[likebreath]

Text serialization is being used in several places of crete-run, vm-node, etc. For the sake of efficiency, they should be replaced by binary serialization.

A driven example is transmitting the guest config file from crete-run to vm-node can take a long time, when the guest config file is non-trivial (such as when we give a concrete file of size 200K as the seed of concolic file, the serialized config file can be over 800K).

By design, "crete/asio" provides a set of read/write communication functions using different serialization format, and they should have the same usage convention. However, it seems "write_serialized_binary() / read_serialized_binary()" can not be directly used as an alternative of "write_serialized_text_xml() / read_serialized_text_xml()".

One concrete example is: when replacing the "_text_xml" pair with "_binary" pair in "RunnerFSM_::transmit_guest_data()" and QemuFSM_::receive_guest_info(), there will be an exception thrown while reading/de-serializing.

Exception info:

std::exception::what: std::exception [crete::err::tag_msg*] = Dynamic exception type: std::length_error std::exception::what: basic_string::resize

[likebreath]

@moralismercatus I have reviewed the related code, and found nothing special. "_text_xml" and "_binary" are identical except they are using different boost serialization formt (text_xml and binary). I also checked the version of boost both on guest and host, and they are both 1.59. To this point, I don't have additional suspects about this problem. Please let me know your inputs. Thanks.

[moralismercatus]

@likebreath Are the guest and host identical platforms? Are they both x64? Just guessing, but it may be an issue with binary compatibility. As a matter of general design, it may not be prudent to make the serialization from guest to host binary.

It may be a better approach to rework how the config is transferred. Essentially, send the binary data as binary and the textual data (the config details) as text.

I'd write a patch for you, but I'm pretty sick right now. It'll probably be a couple days before I can get around to it.

[likebreath]

@moralismercatus Thanks for the quick replay.

You are right. Binary archive from boost serialization is not portable for cross-platform while other formats of archives are (ref).

No hurry about the patch at all. Do you mean a patch for the rework you mentioned? If yes, let's talk about the detail before start the work. Also, it is not a big issue, if the only motivation is to get the guest config file transferred in a more compact way, because for a whole test, the guest config file only needs to be transferred once.

For now, I will just use non-binary serialization for the communication between guest and host. Also, I will add comments about the portability in the header file.

Take care and hope you get well soon.