[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dis
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added |
Date: |
Wed, 20 Sep 2017 00:12:33 +1000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 19/09/17 20:47, Paolo Bonzini wrote:
> On 19/09/2017 12:39, Alexey Kardashevskiy wrote:
>>> No, there's still
>>>
>>> as->dispatch = NULL;
>>> memory_region_update_pending |= root->enabled;
>>> memory_region_transaction_commit();
>>>
>>> when creating the address space, which touches all address spaces.
>>
>> This does not seem helping a lot - my test without such an optimization
>> allocates 2966044 FVs and 2388768 with it, which is just 25%, i.e. worth
>> making a patch but yet getting rid of those nasty virtio-modern address
>> spaces will do a lot better job.
>
> Have you tried resolving aliases that are implemented with containers
> and one subregion?
Yes, for 10 virtio-net and 8 cpus it looks like below, #5 is that shared
thing. And if I use Intel e1000 instead, it is just 4 FVs.
(qemu) info mtree -f -d
FlatView #0
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #1
AS "I/O", root: io
Root memory region: io
FlatView #2
AS "address@hidden", root: address@hidden
Root memory region: address@hidden
FlatView #3
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #4
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #5
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
AS "virtio-net-pci", root: bus master container
Root memory region: (none)
No rendered FlatView
FlatView #6
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #7
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #8
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #9
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #10
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #11
AS "memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
AS "cpu-memory", root: system
Root memory region: system
FlatView #12
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
FlatView #13
AS "virtio-pci-cfg-as", root: virtio-pci-cfg, alias virtio-pci
Root memory region: virtio-pci
>> What is the exact concern about the "[PATCH qemu v3 01/13] memory: Postpone
>> flatview and dispatch tree building till all devices are added"? Is it that
>> you missed that modern AS thing in virtio and thought we can do well even
>> without it?
>
> I am afraid that some of the special sysbus devices (not PCI, those go
> through the bus master DMA region and it's empty on startup) might write
> to memory during initialization.
And somehow QEMU guarantees that all RAM MRs are rendered to FlatViews even
though some might be added via -device (can they btw?)?
>
> Thanks,
>
> Paolo
>
>> Or there is something wrong with the approach?
>
--
Alexey
- [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, (continued)
- [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Alexey Kardashevskiy, 2017/09/18
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/18
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Alexey Kardashevskiy, 2017/09/18
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Alexey Kardashevskiy, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Alexey Kardashevskiy, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Alexey Kardashevskiy, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/19
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added,
Alexey Kardashevskiy <=
- Re: [Qemu-devel] [PATCH qemu v3 01/13] memory: Postpone flatview and dispatch tree building till all devices are added, Paolo Bonzini, 2017/09/19
[Qemu-devel] [PATCH qemu v3 06/13] memory: Remove AddressSpace pointer from AddressSpaceDispatch, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 04/13] memory: Move FlatView allocation to a helper, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 10/13] memory: Store physical root MR in FlatView, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 03/13] memory: Open code FlatView rendering, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 11/13] memory: Share FlatView's and dispatch trees between address spaces, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 09/13] memory: Rename mem_begin/mem_commit/mem_add helpers, Alexey Kardashevskiy, 2017/09/18
[Qemu-devel] [PATCH qemu v3 13/13] memory: Add flat views to HMP "info mtree", Alexey Kardashevskiy, 2017/09/18