From: "zhenzhong.duan" <zhenzhong.duan@oracle.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Feng Jin <joe.jin@oracle.com>
Subject: Re: [PATCH] Parallelize mtrr init between cpus
Date: Wed, 29 Aug 2012 13:16:01 +0800 [thread overview]
Message-ID: <503DA591.4010100@oracle.com> (raw)
In-Reply-To: <5021E2A2.8080606@zytor.com>
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
prev parent reply other threads:[~2012-08-29 5:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-07 7:29 [PATCH] Parallelize mtrr init between cpus zhenzhong.duan
2012-08-07 9:01 ` zhenzhong.duan
2012-08-07 16:32 ` H. Peter Anvin
2012-08-08 2:08 ` zhenzhong.duan
2012-08-08 3:53 ` H. Peter Anvin
2012-08-29 5:16 ` zhenzhong.duan [this message]
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