Hello, while spending some days out of office, I kept thinking about your performance issue. Could it possibly be related to the spinlock that we use to protect the lock metadata? See [1] and [2] for the lock implementation.
I remember when Alex first introduced the use of multiple priorities within a single component (which was actually VirtualBox), we stumbled over the issue that a high-priority thread would eventually keep spinning on a contended spinlock. The spinlock holder, however, was never scheduled anymore because it had a lower priority than the lock applicant. Alex addressed this issue with a NOVA-specific spinlock that maintains priority inheritance. See [3]. [1] https://github.com/genodelabs/genode/blob/master/repos/base/include/base/cancelable_lock.h [2] https://github.com/genodelabs/genode/blob/master/repos/base/src/base/lock/lock.cc [3] https://github.com/genodelabs/genode/blob/master/repos/base-nova/src/base/lock/spin_lock.h It would be interesting to see the spinlock-holding times of the lock's spinlock (by taking rdtsc values when acquiring and releasing the spinlock) in your version of VirtualBox on base-hw/Muen. One would expect the hold times to be just the few cycles. If they are orders of magnitudes higher, we'd need to consider a priority-inheriting spinlock for base-hw. Cheers Norman -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth ------------------------------------------------------------------------------ Don't Limit Your Business. Reach for the Cloud. GigeNET's Cloud Solutions provide you with the tools and support that you need to offload your IT needs and focus on growing your business. Configured For All Businesses. Start Your Cloud Today. https://www.gigenetcloud.com/ _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
