On Thu, Oct 01, 2015 at 08:51:24PM +0200, Marc Lehmann wrote: > 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
Now, I can see much clean patterns. > 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. Hmm, this is because of FS metadata flushes in background. I pushed one patch, can you get it through v3.18 branch? > 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. Cool. > 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 ------------------------------------------------------------------------------ _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
