[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Xenoprof in an HVM domain
I'm looking into getting Xenoprof to tun in an HVM domain, since we will eventually need a profiler for HVM domains to track down areas of poor performance. (HVMs have poor performance? :) ) Being relatively new to OProfile, Xenoprof, and Xen internals, I would appreciate any pointers, tips, and comments on how to work the implementation. I see three basic areas of work. 1. Implement hypercalls in HVM domains. This has been done by Steve Ofsthun of Virtual Iron who contributed his patches to the xen-devel list recently. (Thanks, Steve.) 2. Implement the shared buffer that conveys profile events from the hypervisor to the domain. From my initial crawl through the Xenoprof code (see for example linux-2.6-xen-sparse/arch/i386/oprofile/xenoprof.c) it appears that its setup of the shared buffer via hypercalls and page table updates should work in an HVM domain. Correct me if I'm wrong. 3. Implement an interrupt mechanism for the hypervisor to signal the domain that it has more data in the shared buffer. Xenoprof currently sets up an event channel for this. In my initial hack of the code I discovered that the event channel used by Xenoprof conflicts with the 8259 support in the HVM kernel. Since I use the serial interface to the HVM domain, I am hesitant to remove the 8259 support in my HVM kernel. It appears that I need to either get an event channel to work through qemu, preserving the 8259 functionality, or change Xenoprof in the hypervisor to instruct qemu to issue an interrupt to the domain and change Xenoprof in the domain to run off an interrupt instead of an event channel. Or maybe I don't know what I'm talking about and need to be enlightened by those who know better what the issues are. Any advice is appreciated. Thanks, Steve D. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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