On Wed, Aug 23, 2017 at 11:26:46AM -0700, Linus Torvalds wrote: > On Wed, Aug 23, 2017 at 6:45 AM, Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > > > > Solve the issue by enabling RCU-based table free mechanism when PARAVIRT > > is selected in config. Testing with kernbench doesn't show any notable > > performance impact: > > I wonder if we should just make it unconditional if it doesn't really > show any performance difference. One less config complexity to worry > about (and in this case I'm not so much worried about Kconfig itself, > as just "oh, you have totally different paths in the core VM depending > on PARAVIRT".
In this case we need performance numbers for !PARAVIRT kernel. > That said, the thing to test for these kinds of things is often > heavily scripted loads that just run thousands and thousands of really > small processes, and build up and tear down page tables all the time > because of fork/exit. > > The load I've used occasionally is just "make test" in the git source > tree. Tons and tons of trivial fork/exec/exit things for all those > small tests and shell scripts. Numbers for tight loop of "mmap(MAP_POPULATE); munmap()" might be interesting too for worst case scenario. -- Kirill A. Shutemov _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
