On Tuesday, March 03/20/18, 2018 at 20:10:19 +0530, David Laight wrote: > From: Rahul Lakkireddy > > Sent: 20 March 2018 13:32 > ... > > On High Availability Server, the logs of the failing system must be > > collected as quickly as possible. So, we're concerned with the amount > > of time taken to collect our large on-chip memory. We see improvement > > in doing 256-bit reads at a time. > > Two other options: > > 1) Get the device to DMA into host memory. >
Unfortunately, our device doesn't support doing DMA of on-chip memory. > 2) Use mmap() (and vm_iomap_memory() in your driver) to get direct > userspace access to the (I assume) PCIe memory space. > You can then use whatever copy instructions the cpu has. > (Just don't use memcpy().) > We also need to collect this in kernel space i.e. from crash recovery kernel. Thanks, Rahul
