On Sun, Jan 17, 2016 at 12:00 PM, Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > On 15 January 2016 at 16:09, Dallas Clement <dallas.a.clement@xxxxxxxxx> wrote: >> >> I suspected that might be the case. Is this dirty memory on the >> client side where fio is running or on the target host where the data >> has been written to? > Hi Sitsofe, > It will be on the client side - you aren't waiting for anything to > flush so it can even just queue in the kernel's page cache. > Thanks for confirming that. That definitely explains what I'm seeing then. >> I would like to make fio sync in a similar fashion to what real >> applications would do. Setting sync=1 is probably too aggressive. >> Probably a sync after a given number of blocks would seem more >> realistic. > > Try taking a look at the fsync parameter in the HOWTO: > https://github.com/axboe/fio/blob/fio-2.3/HOWTO#L909 . Thanks. I have been playing around with this fsync parameter. I have tried various numbers ranging from 32 to 128. I do see reasonable numbers now. However throughput is quite a bit less than I was seeing with direct I/O (direct=1). I was expecting I would actually get better performance with buffered I/O. Am I misguided? -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
