On 2012-08-08 11:53, H. Peter Anvin wrote:
On 08/07/2012 07:08 PM, zhenzhong.duan wrote:
2012-08-08 00:32, H. Peter Anvin wrote:
On 08/07/2012 12:29 AM, zhenzhong.duan wrote:
Current code serialize mtrr init with set_atomicity_lock.
Mtrr init is quite slow when we bootup on a hvm with large mem, vcpus
and pci passthroughed devices(eg. 24 vcpus + 90G mem).
It took about ~30 mins to bootup, after patch, it took ~2 min.
When you're saying "HVM" do you mean "Xen HVM"? How does it behave on
native hardware?
-hpa
Yes, I mean Xen HVM. Bootup at same speed as before on baremetal.
Then I would like to know why Xen HVM takes so infernally long. It
isn't a good idea to make gratuitous changes in the main kernel to
work around defects in Xen.
-hpa
Hi,
Sorrry for late response, I have an opportunity to test the patch on an
old G5 with 128 physical CPUS and 1 TB of memory. Arround 0.82 second
time saved.
Depends on cpu count on the system.
I'm curious what's the usage of set_atomicity_lock here? There may be
something I missed. thanks
Before patch:
[ 13.176038] NMI watchdog enabled, takes one hw-pmu counter.
[ 13.176444] Brought up 128 CPUs
[ 13.176688] Total of 128 processors activated (578760.49 BogoMIPS).
[ 14.035223] devtmpfs: initialized
[ 17.277652] PM: Registering ACPI NVS region at 7f76e000 (401408 bytes)
[ 17.279541] print_constraints: dummy:
[ 17.280576] NET: Registered protocol family 16
After patch:
[ 13.094227] smpboot cpu 127: start_ip = 90000
[ 13.185142] NMI watchdog enabled, takes one hw-pmu counter.
[ 13.185599] Brought up 128 CPUs
[ 13.185851] Total of 128 processors activated (578871.80 BogoMIPS).
[ 13.224783] devtmpfs: initialized
[ 16.468002] PM: Registering ACPI NVS region at 7f76e000 (401408 bytes)
[ 16.469706] print_constraints: dummy:
[ 16.470745] NET: Registered protocol family 16
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