Hi Thunder, On Tue, Sep 12, 2017 at 09:00:36PM +0800, Zhen Lei wrote: > Because all TLBI commands should be followed by a SYNC command, to make > sure that it has been completely finished. So we can just add the TLBI > commands into the queue, and put off the execution until meet SYNC or > other commands. To prevent the followed SYNC command waiting for a long > time because of too many commands have been delayed, restrict the max > delayed number. > > According to my test, I got the same performance data as I replaced writel > with writel_relaxed in queue_inc_prod. > > Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com> > --- > drivers/iommu/arm-smmu-v3.c | 42 +++++++++++++++++++++++++++++++++++++----- > 1 file changed, 37 insertions(+), 5 deletions(-)
If we want to go down the route of explicit command batching, I'd much rather do it by implementing the iotlb_range_add callback in the driver, and have a fixed-length array of batched ranges on the domain. We could potentially toggle this function pointer based on the compatible string too, if it shows only to benefit some systems. Will
