On Wed, 20 Nov 2024 at 12:03, Corinna Vinschen <corinna-cyg...@cygwin.com> wrote: > > Hi Teemu, > > On Nov 18 23:28, Teemu Nätkinniemi wrote: > > Hello! > > > > I raised this issue couple of years ago on cygwin-developers. > > The cause of the problem is well known for a long time. The underlying > dlmalloc implementation was never developed for threaded processes, and > Cygwin was originally not multi-thread capable so that wasn't much > of a problem. > > Since that time, Cygwin has moved to multi-threading but we still use > dlmalloc under the hood. The simple approach of just adding a lock > to each call into dlmalloc (see winsup/cygwin/mm/malloc_wrapper.cc) > avoids crashes, but leads to congestion in processes using lots of > memory allocation in lots of threads. > > This is aggravated by the fact that we use malloc within Cygwin itself. > > There were a couple of efforts over the years to replace dlmalloc > with, for instance, ptmalloc3, or to convert dlmalloc to the USE_LOCKS > variant.
Where can we find that variant? > For some reason or other, none of these efforts where > ultimately fruitful yet. Personally I have to admit defeat in trying > to get ptmalloc3 running, more than 10 years ago. > > Anyway. Having said that, anybody being able to come up with a malloc > port which actually works as part of Cygwin *and* avoids the contention > of the current solution will get as many goldstars and plush hippos > (see https://cygwin.com/goldstars/) the person asks for. What about mimalloc? Would that help? Dan -- Dan Shelton - Cluster Specialist Win/Lin/Bsd
