Hi Christoffer, Marc - I just threw this test your way without any explanation. The test loops, does fp arithmetic and checks the truncated result. It could be a little more dynamic have an initial run to get the sum to compare against while looping, different fp hardware may come up with a different sum, but truncation is to 5'th decimal point. The rationale is that if there is any fp/simd corruption one of these runs should fail. I think most likely scenario for that is a world switch in midst of fp operation. I've instrumented (basically add some tracing to vcpu_put()) and validated vcpu_put gets called thousands of time (for v7,v8) for an over night test running two guests/host crunching fp operations. Other then that not sure how to really catch any problems with the patches applied. Obviously this is a huge issues, if this has any problems. If you or Marc have any other ideas I'd be happy to enhance the test. Thanks, Mario On 10/5/2015 8:45 AM, Christoffer Dall wrote: > On Tue, Sep 22, 2015 at 04:34:01PM -0700, Mario Smarduch wrote: >> This is a 2nd itteration for arm64, v1 patches were posted by mistake from an >> older branch which included several bugs. Hopefully didn't waste too much of >> anyones time. >> >> This patch series is a followup to the armv7 fp/simd lazy switch >> implementation, uses similar approach and depends on the series - see >> https://lists.cs.columbia.edu/pipermail/kvmarm/2015-September/016516.html >> >> It's based on earlier arm64 fp/simd optimization work - see >> https://lists.cs.columbia.edu/pipermail/kvmarm/2015-July/015748.html >> >> And subsequent fixes by Marc and Christoffer at KVM Forum hackathon to handle >> 32-bit guest on 64 bit host (and may require more here) - see >> https://lists.cs.columbia.edu/pipermail/kvmarm/2015-August/016128.html >> >> This series has be tested with arm64 on arm64 with several FP applications >> running on host and guest, with substantial decrease on number of >> fp/simd context switches. From about 30% down to 2% with one guest running. >> >> At this time I don't have arm32/arm64 working and hoping Christoffer and/or >> Marc (or anyone) can test 32-bit guest/64-bit host. >> > Did you already have some test infrastructure/applications that I can > reuse for this purpose or do I have to write userspace software? > > -Christoffer > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
