On Thu, Oct 01, 2015 at 02:11:20PM +0200, Marc Lehmann <schm...@schmorp.de> wrote: > WOW, THAT HELPED A LOT. While the peak throughput seems quite a bit lower
Ok, for completeness, here is the full log and a description of what was going on. http://data.plan9.de/f2fs.s64.noinline.full.trace.xz status at the end + some idle time http://ue.tst.eu/d16cf98c72fe9ecbac178ded47a21396.txt It was faster than the reader till roughtly the 1.2TB mark, after which it acquired longish episodes of being <<50MB/s (for example, around 481842.363964), and also periods of ~20kb/s, due to many small WRITE_SYNC's in a row (e.g. at 482329.101222 and 490189.681438, http://ue.tst.eu/cc94978eafc736422437a4ab35862c12.txt). The small WRITE_SYNCs did not always result in this behaviour by the disk, though. After that, it was generally write-I/O bound. Also, the gc seemed to have kicked in at around that time, which is kind of counterproductive. I increased the gc_* values in /sys, but don't know if that had any effect. Most importantly, f2fs always recovered and had periods of much faster writes (>= 120MB/s), so it's not the case that f2fs somehow saturates the internal cache and then becomes slow forever. Overall, the throughput was 83MB/s, which is 20% worse than stock 3.18, but still way beyond what any other filesystem could do. Also, writing 1TB in a single session, with somewhat reduced speed afterwards, would be enough for my purposes, i.e. I can live with that (still, gigabit speeds would be nice of course, as that is the data rate I often deal with). Notwithstanding any other improvements you might implement, f2fs has now officially become my choice for SMR drives, the only remaining thing needed is to convince me of its stability - it seems getting a kernel with truly stable f2fs is a bit of a game of chance still, but I guess confidence will come with more tests and actualy using it in production, which I will do soon. -- The choice of a Deliantra, the free code+content MORPG -----==- _GNU_ http://www.deliantra.net ----==-- _ generation ---==---(_)__ __ ____ __ Marc Lehmann --==---/ / _ \/ // /\ \/ / schm...@schmorp.de -=====/_/_//_/\_,_/ /_/\_\ ------------------------------------------------------------------------------ _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
