> On Jan 26, 2021, at 8:53 PM, Lu Baolu <baolu...@linux.intel.com> wrote:
>
> Hi Chuck,
>
> On 1/26/21 11:52 PM, Chuck Lever wrote:
>>> On Jan 26, 2021, at 1:18 AM, Lu Baolu <baolu...@linux.intel.com> wrote:
>>>
>>> On 2021/1/26 3:31, Chuck Lever wrote:
>>>>> On Jan 25, 2021, at 12:39 PM, Chuck Lever <chuck.le...@oracle.com> wrote:
>>>>>
>>>>> Hello Lu -
>>>>>
>>>>> Many thanks for your prototype.
>>>>>
>>>>>
>>>>>> On Jan 24, 2021, at 9:38 PM, Lu Baolu <baolu...@linux.intel.com> wrote:
>>>>>>
>>>>>> This patch series is only for Request-For-Testing purpose. It aims to
>>>>>> fix the performance regression reported here.
>>>>>>
>>>>>> https://lore.kernel.org/linux-iommu/d81314ed-5673-44a6-b597-090e3cb83...@oracle.com/
>>>>>>
>>>>>> The first two patches are borrowed from here.
>>>>>>
>>>>>> https://lore.kernel.org/linux-iommu/20210107122909.16317-1-yong...@mediatek.com/
>>>>>>
>>>>>> Please kindly help to verification.
>>>>>>
>>>>>> Best regards,
>>>>>> baolu
>>>>>>
>>>>>> Lu Baolu (1):
>>>>>> iommu/vt-d: Add iotlb_sync_map callback
>>>>>>
>>>>>> Yong Wu (2):
>>>>>> iommu: Move iotlb_sync_map out from __iommu_map
>>>>>> iommu: Add iova and size as parameters in iotlb_sync_map
>>>>>>
>>>>>> drivers/iommu/intel/iommu.c | 86 +++++++++++++++++++++++++------------
>>>>>> drivers/iommu/iommu.c | 23 +++++++---
>>>>>> drivers/iommu/tegra-gart.c | 7 ++-
>>>>>> include/linux/iommu.h | 3 +-
>>>>>> 4 files changed, 83 insertions(+), 36 deletions(-)
>>>>>
>>>>> Here are results with the NFS client at stock v5.11-rc5 and the
>>>>> NFS server at v5.10, showing the regression I reported earlier.
>>>>>
>>>>> Children see throughput for 12 initial writers = 4534582.00 kB/sec
>>>>> Parent sees throughput for 12 initial writers = 4458145.56 kB/sec
>>>>> Min throughput per process = 373101.59 kB/sec
>>>>> Max throughput per process = 382669.50 kB/sec
>>>>> Avg throughput per process = 377881.83 kB/sec
>>>>> Min xfer = 1022720.00 kB
>>>>> CPU Utilization: Wall time 2.787 CPU time 1.922 CPU
>>>>> utilization 68.95 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 rewriters = 4542003.12 kB/sec
>>>>> Parent sees throughput for 12 rewriters = 4538024.19 kB/sec
>>>>> Min throughput per process = 374672.00 kB/sec
>>>>> Max throughput per process = 383983.78 kB/sec
>>>>> Avg throughput per process = 378500.26 kB/sec
>>>>> Min xfer = 1022976.00 kB
>>>>> CPU utilization: Wall time 2.733 CPU time 1.947 CPU
>>>>> utilization 71.25 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 readers = 4568632.03 kB/sec
>>>>> Parent sees throughput for 12 readers = 4563672.02 kB/sec
>>>>> Min throughput per process = 376727.56 kB/sec
>>>>> Max throughput per process = 383783.91 kB/sec
>>>>> Avg throughput per process = 380719.34 kB/sec
>>>>> Min xfer = 1029376.00 kB
>>>>> CPU utilization: Wall time 2.733 CPU time 1.898 CPU
>>>>> utilization 69.46 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 re-readers = 4610702.78 kB/sec
>>>>> Parent sees throughput for 12 re-readers = 4606135.66 kB/sec
>>>>> Min throughput per process = 381532.78 kB/sec
>>>>> Max throughput per process = 387072.53 kB/sec
>>>>> Avg throughput per process = 384225.23 kB/sec
>>>>> Min xfer = 1034496.00 kB
>>>>> CPU utilization: Wall time 2.711 CPU time 1.910 CPU
>>>>> utilization 70.45 %
>>>>>
>>>>> Here's the NFS client at v5.11-rc5 with your series applied.
>>>>> The NFS server remains at v5.10:
>>>>>
>>>>> Children see throughput for 12 initial writers = 4434778.81 kB/sec
>>>>> Parent sees throughput for 12 initial writers = 4408190.69 kB/sec
>>>>> Min throughput per process = 367865.28 kB/sec
>>>>> Max throughput per process = 371134.38 kB/sec
>>>>> Avg throughput per process = 369564.90 kB/sec
>>>>> Min xfer = 1039360.00 kB
>>>>> CPU Utilization: Wall time 2.842 CPU time 1.904 CPU
>>>>> utilization 66.99 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 rewriters = 4476870.69 kB/sec
>>>>> Parent sees throughput for 12 rewriters = 4471701.48 kB/sec
>>>>> Min throughput per process = 370985.34 kB/sec
>>>>> Max throughput per process = 374752.28 kB/sec
>>>>> Avg throughput per process = 373072.56 kB/sec
>>>>> Min xfer = 1038592.00 kB
>>>>> CPU utilization: Wall time 2.801 CPU time 1.902 CPU
>>>>> utilization 67.91 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 readers = 5865268.88 kB/sec
>>>>> Parent sees throughput for 12 readers = 5854519.73 kB/sec
>>>>> Min throughput per process = 487766.81 kB/sec
>>>>> Max throughput per process = 489623.88 kB/sec
>>>>> Avg throughput per process = 488772.41 kB/sec
>>>>> Min xfer = 1044736.00 kB
>>>>> CPU utilization: Wall time 2.144 CPU time 1.895 CPU
>>>>> utilization 88.41 %
>>>>>
>>>>>
>>>>> Children see throughput for 12 re-readers = 5847438.62 kB/sec
>>>>> Parent sees throughput for 12 re-readers = 5839292.18 kB/sec
>>>>> Min throughput per process = 485835.03 kB/sec
>>>>> Max throughput per process = 488702.12 kB/sec
>>>>> Avg throughput per process = 487286.55 kB/sec
>>>>> Min xfer = 1042688.00 kB
>>>>> CPU utilization: Wall time 2.148 CPU time 1.909 CPU
>>>>> utilization 88.84 %
>>>>>
>>>>> NFS READ throughput is almost fully restored. A normal-looking throughput
>>>>> result, copied from the previous thread, is:
>>>>>
>>>>> Children see throughput for 12 readers = 5921370.94 kB/sec
>>>>> Parent sees throughput for 12 readers = 5914106.69 kB/sec
>>>>>
>>>>> The NFS WRITE throughput result appears to be unchanged, or slightly
>>>>> worse than before. I don't have an explanation for this result. I applied
>>>>> your patches on the NFS server also without noting improvement.
>>>> Function-boundary tracing shows some interesting results.
>>>> # trace-cmd record -e rpcrdma -e iommu -p function_graph
>>>> --max-graph-depth=5 -g dma_map_sg_attrs
>>>> Some 120KB SGLs are DMA-mapped in a single call to __iommu_map(). Other
>>>> SGLs of
>>>> the same size need as many as one __iommu_map() call per SGL element (which
>>>> would be 30 for a 120KB SGL).
>>>> In v5.10, intel_map_sg() was structured such that an SGL is always handled
>>>> with
>>>> a single call to domain_mapping() and thus always just a single TLB flush.
>>>> My amateur theorizing suggests that the SGL element coalescing done in
>>>> __iommu_map_sg() is not working as well as intel_map_sg() used to, which
>>>> results
>>>> in more calls to domain_mapping(). Not only does that take longer, but it
>>>> creates
>>>> many more DMA maps. Could that also have some impact on device TLB
>>>> resources?
>>>
>>> It seems that more domain_mapping() calls are not caused by
>>> __iommu_map_sg() but __iommu_map().
>>>
>>> Can you please test below changes? It call intel_iommu_map() directly
>>> instead of __iommu_map().
>>>
>>> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
>>> index f5a236e63ded..660d5744a117 100644
>>> --- a/drivers/iommu/intel/iommu.c
>>> +++ b/drivers/iommu/intel/iommu.c
>>> @@ -4916,7 +4916,7 @@ intel_iommu_sva_invalidate(struct iommu_domain
>>> *domain, struct device *dev,
>>> }
>>> #endif
>>>
>>> -static int intel_iommu_map(struct iommu_domain *domain,
>>> +int intel_iommu_map(struct iommu_domain *domain,
>>> unsigned long iova, phys_addr_t hpa,
>>> size_t size, int iommu_prot, gfp_t gfp)
>>> {
>>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>>> index 3d099a31ddca..a1b41fd3fb4e 100644
>>> --- a/drivers/iommu/iommu.c
>>> +++ b/drivers/iommu/iommu.c
>>> @@ -23,8 +23,13 @@
>>> #include <linux/property.h>
>>> #include <linux/fsl/mc.h>
>>> #include <linux/module.h>
>>> +#include <linux/intel-iommu.h>
>>> #include <trace/events/iommu.h>
>>>
>>> +extern int intel_iommu_map(struct iommu_domain *domain,
>>> + unsigned long iova, phys_addr_t hpa,
>>> + size_t size, int iommu_prot, gfp_t gfp);
>>> +
>>> static struct kset *iommu_group_kset;
>>> static DEFINE_IDA(iommu_group_ida);
>>>
>>> @@ -2553,8 +2558,7 @@ static size_t __iommu_map_sg(struct iommu_domain
>>> *domain, unsigned long iova,
>>> phys_addr_t s_phys = sg_phys(sg);
>>>
>>> if (len && s_phys != start + len) {
>>> - ret = __iommu_map(domain, iova + mapped, start,
>>> - len, prot, gfp);
>>> + ret = intel_iommu_map(domain, iova + mapped, start,
>>> len, prot, gfp);
>>>
>>> if (ret)
>>> goto out_err;
>>>
>>> Does it change anything?
>> I removed yesterday's 3-patch series, and applied the above.
>> Not a full restoration, but interesting nonetheless.
>
> Do you mind having a try with all 4 patches?
Much worse. I checked this result several times. I still need to go
look more closely at the patches to see if I merged them together
sensibly.
Children see throughput for 12 initial writers = 3890646.38 kB/sec
Parent sees throughput for 12 initial writers = 3857201.57 kB/sec
Min throughput per process = 322068.31 kB/sec
Max throughput per process = 326518.72 kB/sec
Avg throughput per process = 324220.53 kB/sec
Min xfer = 1034240.00 kB
CPU Utilization: Wall time 3.239 CPU time 1.959 CPU
utilization 60.49 %
Children see throughput for 12 rewriters = 3571855.25 kB/sec
Parent sees throughput for 12 rewriters = 3568989.90 kB/sec
Min throughput per process = 295413.09 kB/sec
Max throughput per process = 300169.31 kB/sec
Avg throughput per process = 297654.60 kB/sec
Min xfer = 1032192.00 kB
CPU utilization: Wall time 3.495 CPU time 2.017 CPU
utilization 57.70 %
Children see throughput for 12 readers = 3485583.19 kB/sec
Parent sees throughput for 12 readers = 3482811.89 kB/sec
Min throughput per process = 287489.16 kB/sec
Max throughput per process = 294395.06 kB/sec
Avg throughput per process = 290465.27 kB/sec
Min xfer = 1024256.00 kB
CPU utilization: Wall time 3.565 CPU time 1.984 CPU
utilization 55.64 %
Children see throughput for 12 re-readers = 3427079.94 kB/sec
Parent sees throughput for 12 re-readers = 3424836.93 kB/sec
Min throughput per process = 283702.56 kB/sec
Max throughput per process = 288727.31 kB/sec
Avg throughput per process = 285589.99 kB/sec
Min xfer = 1030400.00 kB
CPU utilization: Wall time 3.634 CPU time 1.999 CPU
utilization 55.02 %
>> Children see throughput for 12 initial writers = 4852657.22 kB/sec
>> Parent sees throughput for 12 initial writers = 4826730.38 kB/sec
>> Min throughput per process = 403196.09 kB/sec
>> Max throughput per process = 406071.47 kB/sec
>> Avg throughput per process = 404388.10 kB/sec
>> Min xfer = 1041408.00 kB
>> CPU Utilization: Wall time 2.596 CPU time 2.047 CPU
>> utilization 78.84 %
>> Children see throughput for 12 rewriters = 4853900.22 kB/sec
>> Parent sees throughput for 12 rewriters = 4848623.31 kB/sec
>> Min throughput per process = 403380.81 kB/sec
>> Max throughput per process = 405478.53 kB/sec
>> Avg throughput per process = 404491.68 kB/sec
>> Min xfer = 1042944.00 kB
>> CPU utilization: Wall time 2.589 CPU time 2.048 CPU
>> utilization 79.12 %
>> Children see throughput for 12 readers = 4938124.12 kB/sec
>> Parent sees throughput for 12 readers = 4932862.08 kB/sec
>> Min throughput per process = 408768.81 kB/sec
>> Max throughput per process = 413879.25 kB/sec
>> Avg throughput per process = 411510.34 kB/sec
>> Min xfer = 1036800.00 kB
>> CPU utilization: Wall time 2.536 CPU time 1.906 CPU
>> utilization 75.16 %
>> Children see throughput for 12 re-readers = 4992115.16 kB/sec
>> Parent sees throughput for 12 re-readers = 4986102.07 kB/sec
>> Min throughput per process = 411103.00 kB/sec
>> Max throughput per process = 420302.97 kB/sec
>> Avg throughput per process = 416009.60 kB/sec
>> Min xfer = 1025792.00 kB
>> CPU utilization: Wall time 2.497 CPU time 1.887 CPU
>> utilization 75.57 %
>> NFS WRITE throughput improves significantly. NFS READ throughput
>> improves somewhat, but not to the degree it did with yesterday's
>> patch series.
>> function_graph shows a single intel_iommu_map() is used more
>> frequently, but the following happens on occasion:
>
> This is because the pages are not physically contiguous, __iommu_map_sg
> can't coalesce them.
Understood, but why was physical contiguity not a problem for the
intel_map_sg() function removed by commit c588072bba6b ("iommu/vt-d:
Convert intel iommu driver to the iommu ops")? That version of the
function did no such checking, and simply invoked domain_mapping()
once for the entire SGL. Was that not safe to do?
(Feel free to tell me where I'm wrong, I'm really quite a neophyte
with this level of IOMMU detail).
> If there's no full restoration with all four patches, it could be due to
> ping-pongs between iommu core and the vendor iommu driver with indirect
> calls. Hence a possible solution is to add an iommu_ops->map_sg() so
> that all scatter gathered items could be handled in a single function as
> before. This has already proposed by Isaac J. Manjarres.
>
> https://lore.kernel.org/linux-iommu/1610376862-927-5-git-send-email-isa...@codeaurora.org/
That was one of the first things I tried. However, Isaac's patches
don't provide an Intel version of .map_sg, so I made one up based on
__iommu_map_sg, which basically copied the physical page checking
mentioned above. It didn't perform very well.
I could try again with a .map_sg that works like the old intel_map_sg()
function, perhaps.
> Best regards,
> baolu
>
>> 395.678889: funcgraph_entry: | dma_map_sg_attrs() {
>> 395.678889: funcgraph_entry: | iommu_dma_map_sg() {
>> 395.678890: funcgraph_entry: 0.257 us | iommu_get_dma_domain();
>> 395.678890: funcgraph_entry: 0.255 us |
>> iommu_dma_deferred_attach();
>> 395.678891: funcgraph_entry: |
>> iommu_dma_sync_sg_for_device() {
>> 395.678891: funcgraph_entry: 0.253 us | dev_is_untrusted();
>> 395.678891: funcgraph_exit: 0.773 us | }
>> 395.678892: funcgraph_entry: 0.250 us | dev_is_untrusted();
>> 395.678893: funcgraph_entry: | iommu_dma_alloc_iova()
>> {
>> 395.678893: funcgraph_entry: | alloc_iova_fast() {
>> 395.678893: funcgraph_entry: 0.255 us |
>> _raw_spin_lock_irqsave();
>> 395.678894: funcgraph_entry: 0.375 us |
>> __lock_text_start();
>> 395.678894: funcgraph_exit: 1.435 us | }
>> 395.678895: funcgraph_exit: 2.002 us | }
>> 395.678895: funcgraph_entry: 0.252 us | dma_info_to_prot();
>> 395.678895: funcgraph_entry: | iommu_map_sg_atomic() {
>> 395.678896: funcgraph_entry: | __iommu_map_sg() {
>> 395.678896: funcgraph_entry: 1.675 us | intel_iommu_map();
>> 395.678898: funcgraph_entry: 1.365 us | intel_iommu_map();
>> 395.678900: funcgraph_entry: 1.373 us | intel_iommu_map();
>> 395.678901: funcgraph_entry: 1.378 us | intel_iommu_map();
>> 395.678903: funcgraph_entry: 1.380 us | intel_iommu_map();
>> 395.678905: funcgraph_entry: 1.380 us | intel_iommu_map();
>> 395.678906: funcgraph_entry: 1.378 us | intel_iommu_map();
>> 395.678908: funcgraph_entry: 1.380 us | intel_iommu_map();
>> 395.678910: funcgraph_entry: 1.345 us | intel_iommu_map();
>> 395.678911: funcgraph_entry: 1.342 us | intel_iommu_map();
>> 395.678913: funcgraph_entry: 1.342 us | intel_iommu_map();
>> 395.678915: funcgraph_entry: 1.395 us | intel_iommu_map();
>> 395.678916: funcgraph_entry: 1.343 us | intel_iommu_map();
>> 395.678918: funcgraph_entry: 1.350 us | intel_iommu_map();
>> 395.678920: funcgraph_entry: 1.395 us | intel_iommu_map();
>> 395.678921: funcgraph_entry: 1.342 us | intel_iommu_map();
>> 395.678923: funcgraph_entry: 1.350 us | intel_iommu_map();
>> 395.678924: funcgraph_entry: 1.345 us | intel_iommu_map();
>> 395.678926: funcgraph_entry: 1.345 us | intel_iommu_map();
>> 395.678928: funcgraph_entry: 1.340 us | intel_iommu_map();
>> 395.678929: funcgraph_entry: 1.342 us | intel_iommu_map();
>> 395.678931: funcgraph_entry: 1.335 us | intel_iommu_map();
>> 395.678933: funcgraph_entry: 1.345 us | intel_iommu_map();
>> 395.678934: funcgraph_entry: 1.337 us | intel_iommu_map();
>> 395.678936: funcgraph_entry: 1.305 us | intel_iommu_map();
>> 395.678938: funcgraph_entry: 1.380 us | intel_iommu_map();
>> 395.678939: funcgraph_entry: 1.365 us | intel_iommu_map();
>> 395.678941: funcgraph_entry: 1.370 us | intel_iommu_map();
>> 395.678943: funcgraph_entry: 1.365 us | intel_iommu_map();
>> 395.678945: funcgraph_entry: 1.482 us | intel_iommu_map();
>> 395.678946: funcgraph_exit: + 50.753 us | }
>> 395.678947: funcgraph_exit: + 51.348 us | }
>> 395.678947: funcgraph_exit: + 57.975 us | }
>> 395.678948: funcgraph_exit: + 58.700 us | }
>> 395.678953: xprtrdma_mr_map: task:64127@5 mr.id=104 nents=30
>> 122880@0xc5e467fde9380000:0xc0011103 (TO_DEVICE)
>> 395.678953: xprtrdma_chunk_read: task:64127@5 pos=148
>> 122880@0xc5e467fde9380000:0xc0011103 (more)
>> --
>> Chuck Lever
--
Chuck Lever
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