On Sunday 12 November 2006 11:49, Laurent Desnogues wrote: > Daniel Jacobowitz a écrit : > > Straight qemu with my previously posted MIPS patches takes 6:13 to > > start and reboot a MIPS userspace (through init, so lots of fork/exec). > > > > Thiemo's patch, which flushes the whole jump buffer, cuts it to 1:40. > > > > A patch which finds the entries which need to be flushed more > > efficiently cuts it to 1:21. > > > > A patch which flushes up to 1/32nd of the jump buffer indiscriminately > > cuts it to 1:11-1:13. > > Warning: I don't know anything about the Qemu MMU implementation > so this question is perhaps stupid :) > > Did you try to benchmark some user space applications with the > various implementations you propose? The boot of a Linux kernel > is quite heavy on various kinds of flushes and so is very > different from "standard" applications.
MIPS is different because it has a relatively small software managed TLB. Other targets have a hardware managed TLB. On a hardware managed TLB the OS treats it as if it were infinite size, and invalidation only occurs when a OS changes the mappings. On a software managed TLB "flushes" are more likely to occur during normal operation as TLB slots are reused. Paul _______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
