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Re: [Xen-devel] write_tsc in a PV domain?
| To: | Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, Jeremy Fitzhardinge <jeremy@xxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] write_tsc in a PV domain? |
| From: | Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
| Date: | Mon, 31 Aug 2009 20:06:02 +0100 |
| Cc: | "Xen-Devel \(E-mail\)" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> |
| Delivery-date: | Mon, 31 Aug 2009 12:06:36 -0700 |
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| Thread-topic: | [Xen-devel] write_tsc in a PV domain? |
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On 31/08/2009 19:11, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote: > I have yet to get a measurement of either syscall that > is better than 2.5x WORSE than emulating rdtsc. On > my dual-core Conroe (Intel E6850) with 64-bit Xen and > 32-bit dom0, I get approximately: > > rdtsc native: 22ns > softtsc (rdtsc emulated): 360ns Trap-and-emulate in 360ns seems astoundingly good. Perhaps too good to be true? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
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