Dong, Eddie wrote: > Avi Kivity wrote: > >> Dong, Eddie wrote: >> >>> This patch provides short cut handling for light weight VM Exit, >>> which can boost KB performance 11% under FC5 guest. >>> Any comments? >>> >> While the patch looks good, it kills FC6 x86_64 boot with a double >> fault. Guest kernel is 2.6.18-1.2798. dmesg says >> >> inject_page_fault: double fault 0x7fff79b58fd8 @ 0xffffffff8025cca1 >> >> > I think I know the reason, the SYSCALL_MASK & LSTAR update in guest > needs to > update the physical side MSR after this patch. With this update in > vmx_set_msr, > I get it up on a RHEL5U 64 bits guest but no time to check the detail > performance > gain yet. (will report after May day national holiday 5/1--5/8 in PRC) > > BTW, I have another patch in hand to further reduce MSR save/restore and > thus > improve performance more for lightweight VM Exit. Base on my observation > for FC5 32 bits > guest, 93% VM Exit will fall into the lightweight path. > >
I measured 650 cycles saved from a total of 5300 before the patch. The patch had a bug where it would exit to userspace if need_resched() was true. This can reduce performance on a high context switch scenario (many virtual machines). I fixed that, and also a minor coding style issue, and applied. Enjoy your holiday :) -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
