Re: [PATCH v3] iommu/dma: Use NUMA aware memory allocations in __iommu_dma_alloc_pages()

From: John Garry
Date: Fri Nov 23 2018 - 11:41:18 EST

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On 21/11/2018 16:57, Will Deacon wrote:

On Wed, Nov 21, 2018 at 04:47:48PM +0000, John Garry wrote:

On 21/11/2018 16:07, Will Deacon wrote:

On Wed, Nov 21, 2018 at 10:54:10PM +0800, John Garry wrote:

From: Ganapatrao Kulkarni <ganapatrao.kulkarni@xxxxxxxxxx>

Change function __iommu_dma_alloc_pages() to allocate pages for DMA from
respective device NUMA node. The ternary operator which would be for
alloc_pages_node() is tidied along with this.

We also include a change to use kvzalloc() for kzalloc()/vzalloc()
combination.

Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@xxxxxxxxxx>
[JPG: Added kvzalloc(), drop pages ** being device local, tidied ternary operator]
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>

Weird, you're missing a diffstat here.

Anyway, the patch looks fine to me, but it would be nice if you could
justify the change with some numbers. Do you actually see an improvement

>from this change?

Hi Will,

Ah, I missed adding my comments explaining the motivation. It would be
better in the commit log. Anyway, here's the snippet:

" ... as mentioned in [3], dma_alloc_coherent() uses the locality
information from the device - as in direct DMA - so this patch is just
applying this same policy.

[3]
https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1692998.html";

Yes, please add to this to the commit log.

Sure,

I did have some numbers to show improvement in some scenarios when I tested
this a while back which I'll dig out.

However I would say that some scenarios will improve and the opposite for
others with this change, considering different conditions in which DMA
memory may be used.

Well, if you can show that it's useful in some cases and not catastrophic in
others, then I think shooting for parity with direct DMA is a reasonable
justification for the change.

So I have done some more testing with our SoC crypto engine, using tcrypt module. The reason I used this device was because we can utilise a local device per socket in the system, unlike other DMAing devices, which generally only exist on a single socket (for us, anyway).

Overall the results aren't brilliant - as expected - but show a general marginal improvement. Here's some figures:

Summary:
Average diff +0.9%
Max diff +1.5%
Min diff +0.2%

Test Ops/second before after diff %

async ecb(aes) encrypt
test 0 (128 bit key, 16 byte blocks) 68717 69057 0.5
test 1 (128 bit key, 64 byte blocks): 72633 73163 0.7
test 2 (128 bit key, 256 byte blocks): 71475 72076 0.8
test 3 (128 bit key, 1024 byte blocks): 66819 67467 1.0
test 4 (128 bit key, 8192 byte blocks): 38237 38495 0.7
test 5 (192 bit key, 16 byte blocks): 70273 71079 1.2
test 6 (192 bit key, 64 byte blocks): 72455 73292 1.2
test 7 (192 bit key, 256 byte blocks): 71085 71876 1.1
test 8 (192 bit key, 1024 byte blocks): 65891 66576 1.0
test 9 (192 bit key, 8192 byte blocks): 34846 35061 0.6
test 10 (256 bit key, 16 byte blocks): 72927 73762 1.2
test 11 (256 bit key, 64 byte blocks): 72361 73207 1.2
test 12 (256 bit key, 256 byte blocks): 70907 71602 1.0
test 13 (256 bit key, 1024 byte blocks):65035 65653 1.0
test 14 (256 bit key, 8192 byte blocks):32835 32998 0.5
async ecb(aes) decrypt
test 0 (128 bit key, 16 byte blocks) 68384 69130 1.1
test 1 (128 bit key, 64 byte blocks): 72645 73133 0.7
test 2 (128 bit key, 256 byte blocks): 71523 71912 0.5
test 3 (128 bit key, 1024 byte blocks): 66902 67258 0.5
test 4 (128 bit key, 8192 byte blocks): 38260 38434 0.5
test 5 (192 bit key, 16 byte blocks): 70301 70816 0.7
test 6 (192 bit key, 64 byte blocks): 72473 73064 0.8
test 7 (192 bit key, 256 byte blocks): 71106 71663 0.8
test 8 (192 bit key, 1024 byte blocks): 65915 66363 0.7
test 9 (192 bit key, 8192 byte blocks): 34876 35006 0.4
test 10 (256 bit key, 16 byte blocks): 72969 73519 0.8
test 11 (256 bit key, 64 byte blocks): 72404 72925 0.7
test 12 (256 bit key, 256 byte blocks): 70861 71350 0.7
test 13 (256 bit key, 1024 byte blocks):65074 65485 0.6
test 14 (256 bit key, 8192 byte blocks):32861 32974 0.3
async cbc(aes) encrypt
test 0 (128 bit key, 16 byte blocks) 58306 59131 1.4
test 1 (128 bit key, 64 byte blocks): 61647 62565 1.5
test 2 (128 bit key, 256 byte blocks): 60841 61666 1.4
test 3 (128 bit key, 1024 byte blocks): 57503 58204 1.2
test 4 (128 bit key, 8192 byte blocks): 34760 35055 0.9
test 5 (192 bit key, 16 byte blocks): 59684 60452 1.3
test 6 (192 bit key, 64 byte blocks): 61705 62516 1.3
test 7 (192 bit key, 256 byte blocks): 60678 61426 1.2
test 8 (192 bit key, 1024 byte blocks): 56805 57487 1.2
test 9 (192 bit key, 8192 byte blocks): 31836 32093 0.8
test 10 (256 bit key, 16 byte blocks): 61961 62785 1.3
test 11 (256 bit key, 64 byte blocks): 61584 62427 1.4
test 12 (256 bit key, 256 byte blocks): 60407 61246 1.4
test 13 (256 bit key, 1024 byte blocks):56135 56868 1.3
test 14 (256 bit key, 8192 byte blocks):30128 30380 0.8
async cbc(aes) decrypt
test 0 (128 bit key, 16 byte blocks) 58555 59044 0.8
test 1 (128 bit key, 64 byte blocks): 61853 62589 1.2
test 2 (128 bit key, 256 byte blocks): 60992 61728 1.2
test 3 (128 bit key, 1024 byte blocks): 57591 58250 1.1
test 4 (128 bit key, 8192 byte blocks): 34796 35064 0.8
test 5 (192 bit key, 16 byte blocks): 59843 60506 1.1
test 6 (192 bit key, 64 byte blocks): 61808 62521 1.2
test 7 (192 bit key, 256 byte blocks): 60800 61445 1.1
test 8 (192 bit key, 1024 byte blocks): 56949 57513 1.0
test 9 (192 bit key, 8192 byte blocks): 31890 32107 0.7
test 10 (256 bit key, 16 byte blocks): 62109 62778 1.1
test 11 (256 bit key, 64 byte blocks): 61748 62418 1.1
test 12 (256 bit key, 256 byte blocks): 60604 61226 1.0
test 13 (256 bit key, 1024 byte blocks):56277 56845 1.0
test 14 (256 bit key, 8192 byte blocks):30165 30340 0.6
sync xts(aes) encrypt
test 0 (256 bit key, 16 byte blocks): 59501 59742 0.4
test 1 (256 bit key, 64 byte blocks): 62894 63249 0.6
test 2 (256 bit key, 256 byte blocks): 62074 62476 0.7
test 3 (256 bit key, 1024 byte blocks): 58569 58894 0.6
test 4 (256 bit key, 8192 byte blocks): 35271 35462 0.5
test 5 (512 bit key, 16 byte blocks): 60749 61174 0.7
test 6 (512 bit key, 64 byte blocks): 62760 63148 0.6
test 7 (512 bit key, 256 byte blocks): 61625 61928 0.5
test 8 (512 bit key, 1024 byte blocks): 57162 57452 0.5
test 9 (512 bit key, 8192 byte blocks): 30582 30718 0.4
async xts(aes) decrypt
test 0 (256 bit key, 16 byte blocks): 59423 59587 0.3
test 1 (256 bit key, 64 byte blocks): 62849 62974 0.2
test 2 (256 bit key, 256 byte blocks): 61884 62231 0.6
test 3 (256 bit key, 1024 byte blocks): 58402 58699 0.5
test 4 (256 bit key, 8192 byte blocks): 35244 35353 0.3
test 5 (512 bit key, 16 byte blocks): 60693 60882 0.3
test 6 (512 bit key, 64 byte blocks): 62671 62896 0.4
test 7 (512 bit key, 256 byte blocks): 61488 61722 0.4
test 8 (512 bit key, 1024 byte blocks): 57092 57261 0.3
test 9 (512 bit key, 8192 byte blocks): 30572 30655 0.3
sync ctr(aes) encrypt
test 0 (128 bit key, 16 byte blocks): 59673 9926 0.4
test 1 (128 bit key, 64 byte blocks): 62738 63024 0.5
test 2 (128 bit key, 256 byte blocks): 61841 62171 0.5
test 3 (128 bit key, 1024 byte blocks): 58374 58633 0.4
test 4 (128 bit key, 8192 byte blocks): 35137 35273 0.4
test 5 (192 bit key, 16 byte blocks): 60736 61049 0.5
test 6 (192 bit key, 64 byte blocks): 62718 63081 0.6
test 7 (192 bit key, 256 byte blocks): 61652 61973 0.5
test 8 (192 bit key, 1024 byte blocks): 57709 58002 0.5
test 9 (192 bit key, 8192 byte blocks): 32171 32306 0.4
test 10 (256 bit key, 16 byte blocks): 63000 63428 0.7
test 11 (256 bit key, 64 byte blocks): 62594 63027 0.7
test 12 (256 bit key, 256 byte blocks): 61452 61845 0.6
test 13 (256 bit key, 1024 byte blocks):57019 57346 0.6
test 14 (256 bit key, 8192 byte blocks):30422 30544 0.4
async ctr(aes) decrypt
test 0 (128 bit key, 16 byte blocks): 59488 59994 0.9
test 1 (128 bit key, 64 byte blocks): 62651 63173 0.8
test 2 (128 bit key, 256 byte blocks): 61778 62464 1.1
test 3 (128 bit key, 1024 byte blocks): 58290 58909 1.1
test 4 (128 bit key, 8192 byte blocks): 35115 35358 0.7
test 5 (192 bit key, 16 byte blocks): 60590 61244 1.1
test 6 (192 bit key, 64 byte blocks): 62604 63296 1.1
test 7 (192 bit key, 256 byte blocks): 61540 62199 1.1
test 8 (192 bit key, 1024 byte blocks): 57577 58149 1.0
test 9 (192 bit key, 8192 byte blocks): 32146 32368 0.7
test 10 (256 bit key, 16 byte blocks): 62852 63610 1.2
test 11 (256 bit key, 64 byte blocks): 62523 63276 1.2
test 12 (256 bit key, 256 byte blocks): 61356 62049 1.1
test 13 (256 bit key, 1024 byte blocks):56943 57546 1.1
test 14 (256 bit key, 8192 byte blocks):30399 30593 0.6

Let me know if any more questions or comments.

Thanks,
John

Will

.

Next message: Jessica Yu: "[PATCH v2] module: make it clearer when we're handling kallsyms symbols vs exported symbols"
Previous message: Josh Poimboeuf: "Re: [PATCH] x86: only use ERMS for user copies for larger sizes"
In reply to: Will Deacon: "Re: [PATCH v3] iommu/dma: Use NUMA aware memory allocations in __iommu_dma_alloc_pages()"
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