Date: Sun, 4 Mar 2018 11:55:05 -0800 From: Mark Millard <marklmi26-fbsd@yahoo.com> To: bob prohaska <fbsd@www.zefox.net>, Freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Is maximum swap usage tunable? Message-ID: <B6B18BBD-0510-4F19-A09A-43BFB200CFA5@yahoo.com> In-Reply-To: <1EB91943-C141-4EA6-AD63-A629525E206E@yahoo.com> References: <1EB91943-C141-4EA6-AD63-A629525E206E@yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2018-Mar-4, at 11:51 AM, Mark Millard <marklmi26-fbsd at yahoo.com> wrote: > bob prohaska fbsd at www.zefox.net write on > Sun Mar 4 18:28:36 UTC 2018: > >> The worst-case events were >> dT: 10.002s w: 10.000s >> L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name >> . . . >> 0 1 0 13 5.6 1 28 5674 88.3 da0b >> . . . > > I'll note that (1000s/ms)*(ms/w) != 1/(w/s) here > (and frequently). (ms/r and r/s are similarly related.) I was interrupted and screwed up the calculation text without noticing: (s/(1000ms))*(ms/w) != 1/(w/s) > It appears that ms/w counts time with the write > waiting in a queue to be executed or some such but > w/s is strictly the observed rate of writes happening, > independent of how long each waited. (The columns need > not refer to the exact same time frame either as far > as I can tell.) > > [Someone may know the actual details of what ms/w > and ms/r spans. The above includes guess work.] > > Also: 5674 ms/w is over 5 seconds "per write" (probably > a "mean" form of average, but possibly only one write > covered). I doubt that we can be sure of much about the > stages involved in that large figure if "time waiting > in the queue" and later stages of the processing all > contribute. === Mark Millard marklmi at yahoo.com ( markmi at dsl-only.net is going away in 2018-Feb, late) === Mark Millard marklmi at yahoo.com ( markmi at dsl-only.net is going away in 2018-Feb, late)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?B6B18BBD-0510-4F19-A09A-43BFB200CFA5>