On Mon, Aug 08, 2016 at 12:30:18PM +0000, Boylston, Brian wrote: > I used NVML 1.1 for the measurements. In this version and with the hardware > that I used, the pmem_persist() flow is: Please don't use crap like NVML, given that the people behind it don't seem to understand persistency at all. > Perhaps you mean pmem_msync() here? pmem_msync() calls msync(), but > pmem_persist() does not. pmem_persist is misnamed then, don't use it. > > At which point > > you've lost most of the advantages using movnt. Ross researches into > > possibilities of allowing more efficient userspace implementation but > > currently there are none. > > Apart from the current performance discussion, if the metadata for a file > is already established (file created, space allocated by explicit writes(), > and everything synced), then if I map it and do pmem_memcpy_persist(), > are there any "ongoing" metadata updates that would need to be flushed > (besides timestamps)? Yes. For example because every write might mean a new space allocating if using reflinks or a COW file system. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
