I've have looked at paralelization of the module loading code some time ago, albeit with a slightly different use case in mind. I eventually abandoned it (at least temporarily) because I could not get it to work correctly for all use cases.
I do think that doing this is a good idea, but I think it will have to be done with a very steady hand. E.g., if I patch your changes in right now I get about 10 random tests failing on every test suite run, so it's clear that you are introducing a race somewhere. We will also need to have a discussion about what kind of work can be done eagerly, as I believe we are trying to a lot of things very lazily (which unfortunately makes efficient paralelization more complicated). On 13 April 2017 at 06:34, Scott Smith via lldb-dev <lldb-dev@lists.llvm.org > wrote: > The POSIX dynamic loader processes one module at a time. If you have a > lot of shared libraries, each with a lot of symbols, this creates unneeded > serialization (despite the use of TaskRunners during symbol loading, there > is still quite a bit of serialization when loading a library). > > In order to parallelize this, I actually had to do two things. Neither > one makes any difference, only the combination improves performance (I left > them as separate patches for clarity): > > 1. Change the POSIX dynamic loader to fork each module into its own > thread. I didn't use TaskRunner because some of the called functions use > TaskRunner, and it isn't recursion safe. The final modules are added to > the list in the original order despite whatever order the threads finish. > > 2. Change Module::AppendImpl to fire off some expensive work as a separate > thread. > > These two changes bring startup time down from 36 (assuming the previously > mentioned crc changes) seconds to 11. It doesn't improve efficiency, it > just increases parallelism. > > > _______________________________________________ > lldb-dev mailing list > lldb-dev@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev > >
_______________________________________________ lldb-dev mailing list lldb-dev@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
