On Tue, 5 May 2020, Paolo Bonzini wrote: > >>> Since this is becoming a generic API (good!!), maybe we can discuss > >>> possible ways to optimize gathering of stats in mass? > >> Sure, the idea of a binary format was considered from the beginning in > >> [1], and it can be done either together with the current filesystem, or > >> as a replacement via different mount options. > > > > ASCII stats are not scalable. A binary format is definitely the way to go. > > I am totally in favor of having a binary format, but it should be > introduced as a separate series on top of this one---and preferably by > someone who has already put some thought into the problem (which > Emanuele and I have not, beyond ensuring that the statsfs concept and > API is flexible enough). > The concern is that once this series is merged then /sys/kernel/stats could be considered an ABI and there would be a reasonable expectation that it will remain stable, in so far as the stats that userspace is interested in are stable and not obsoleted. So is this a suggestion that the binary format becomes complementary to statsfs and provide a means for getting all stats from a single subsystem, or that this series gets converted to such a format before it is merged? > ASCII stats are necessary for quick userspace consumption and for > backwards compatibility with KVM debugfs (which is not an ABI, but it's > damn useful and should not be dropped without providing something as > handy), so this is what this series starts from. >
