-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Frank Ch. Eigler wrote: > Hi - > > It has come to my attention that the preempt-rt patch suite > deliberately defeats the potential concurrency intended by systemtap's > use of rwlocks to permit concurrent readers of various data > structures. Since systemtap's probe handlers are all atomic, > nonblocking, nonpreemptable, it does not seem like there is any > real-time-oriented benefit in this. What can we do to work around > this and permit reader concurrency again in preempt-rt? > The reason it "defeats" the concurrent behavior is that it's really complicated to have concurrent readers with Priority Inheritance, so the initial cut of rtmutexes serialized all lock accesses. Steven has posted a patch for comment (with no takers yet) that implements r/w locks with concurrent readers and PI. We've just started running it on the MRG RT kernel with some success, but I wouldn't say that it's ready for prime time. You're welcome to help test it though... Clark -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkgcd+gACgkQHyuj/+TTEp2JCwCg4ZhqdqHCb9SZM+zrkKcyohtL 2coAoKLyUGZnRKha5NH7UDrM1QsP5ZaE =FQas -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
