[EMAIL PROTECTED] wrote: > Avi Kivity wrote: >> Jan Kiszka wrote: >>> Avi Kivity wrote: >>> >>>> Liu, Eric E wrote: >>>> >>>>> >>>>> Since we already have had debugfs_entries and some other kernel >>>>> debug mechanism to use, does this kvmtrace make sense? Any >>>>> comment is welcomed. >>>> This looks very useful. While kvm_stat provides good data, this >>>> is much more in depth. >>>> >>>> The kernel already contains a method of transferring percpu data to >>>> userspace; see Documentation/filesystems/relay.txt. It supports >>>> mmap() and read(). Please see if it is a good fit. >>>> >>> >>> I would also suggest to use the new kernel standard for >>> instrumentation: trace_mark(). >>> >>> This would also allow to reuse the trace points with other tracer >>> and maybe even obsolete a separate transportation channel, e.g. >>> when LTTng is once :-/ merged. >>> >> >> Can one have markers automatically recorded? Or do you need to >> connect the marker with a logging function? > > Yes, of course you need a probe function. Either your own one, or one > provided by other tracers. > >> >> If the latter, it's too difficult to use. > > I don't think it is. Check linux/samples/markers/probe-example.c. BTW, > RCU-Trace (not yet mainlined) make use of markers as well, see -rt. > > And in contrast to the suggested implementation, markers have less > impact on the code if built-in but disabled. So there would be no > reasons for not shipping kvm production binaries that are prepared to > be traced. > > But if you prefer the inlined version, I bet you'll have to hide it > from reviewers at LKML. ;) > > Jan
Thanks for your comments, and I think that using relayfs and trace_mark() is more reasonable, if it makes sense, I will modify the patches according to these. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
