hi, > [email protected] (YAMAMOTO Takashi) wrote: >> hi, >> >> what's the status of emap and pipe? >> > > If I remember correctly, I could not get real performance improvement > of pipe with UVM emap. Higher chances are that it would improve socket > performance. Also, pipe has direct I/O disabled (PIPE_NODIRECT) due > to some rare lock-ups when switching between direct/buffered. AFAIK, > we have this bug since netbsd-3 times or even earlier.
can you provide a recipe to reproduce the lock-up? > > However, I tend to question whether UVM emap was a right approach to > the problem. For amd64, we should definitely have a direct mapping > of kernel space (I was planning to revive the patch written by chs@, > but ran out of time) and encourage our users to use amd64 instead > of i386. Most other architectures have a segment for direct mapping. > I wonder if we could help i386 with large pages for kernel space.. the real problem for i386 is kva shortage. direct-mapping only limited part of physical memory would work, tho. (call the rest of memory highmem!) YAMAMOTO Takshi > > -- > Mindaugas
