https://bugzilla.kernel.org/show_bug.cgi?id=218739 --- Comment #5 from mlevitsk@xxxxxxxxxx --- I tested several approaches to eliminate the issue, but none of them seem to be very robust. In particular: - I tried to clflush a global memory location outside of the loop, then access it. 0 LLC misses still happen, once in a while. - I also tried to access a location on the stack. Here the test started failing on INTEL_ARCH_TOPDOWN_SLOTS_INDEX sometimes, I am not sure why. I did push/pop, maybe ucode is smart enough to elide this? I now found a new and a more or less robust solution, which is to clflush on each loop iteration. That both increases the chances of at least one clflush working and it should also confuse the speculation code enough. It survived about 4 hours of testing. I attached a draft patch with this solution, if you think that it is reasonable, I'll send it to LKML. Note that I dropped the mfence instruction thinking that it doesn't help much since it helps with memory loads/stores while we clflush the memory which is fetched for code execution. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
