From: Madhavan T. Venkataraman > Sent: 28 July 2020 19:52 ... > trampfd faults are instruction faults that go through a different code path than > the one that calls handle_mm_fault(). Perhaps, it is the handle_mm_fault() that > is time consuming. Could you clarify? Given that the expectation is a few instructions in userspace (eg to pick up the original arguments for a nested call) the (probable) thousands of clocks taken by entering the kernel (especially with page table separation) is a massive delta. If entering the kernel were cheap no one would have added the DSO functions for getting the time of day. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
