[Libguestfs] [PATCH nbdkit v2 3/3] filters: stats: Add flush stats

[Nir Soffer]

On Mon, Dec 2, 2019 at 12:28 PM Richard W.M. Jones <rjones at redhat.com> wrote:
>
>
> I have pushed some parts of these patches in order to reduce the delta
> between your patches and upstream.  However still some problems with
> the series:
>
> Patch 1: Same problem with scale as discussed before.

I addressed this here:
https://www.redhat.com/archives/libguestfs/2019-December/msg00011.html

> Patch 2: At least the documentation needs to be updated since it no
> longer matches what is printed.  The idea of collecting the time taken
> in each operation is good on its own, so I pushed that part of it
> along with small const-correctness and whitespace fixes:
>
>   https://github.com/libguestfs/nbdkit/commit/f280530d7d042d5e8f100125ab0618515de52142

Thanks for pushing it.

> Why don't we show the total time and time / operation on each line of
> output (ie. per operation), instead of synthesizing the total by
> adding up reads and writes?

I think that synthesizing totals give better view on total application
throughput, and add
information that was not available before, like total number of ops.
Showing two rate
values per operation looks confusing to me.

But how about this:

----------------------------------------------
total: 2299 ops, 2.172 s, 6.00 GiB, 2.76 GiB/s
       520.73 MiB/s write, 2.23 GiB/s zero
-----------------------------------------------
write: 1271 ops, 0.356 s, 1.13 GiB, 3.19 GiB/s
zero: 1027 ops, 0.012 s, 4.86 GiB, 405.00 GiB/s
extents: 1 ops, 0.000 s, 2.00 GiB, 485.29 GiB/s
flush: 2 ops, 1.252 s

> Patch 3: The idea of collecting flush stats is good so I pushed that
> part, as well as updating the documentation:
>
>   https://github.com/libguestfs/nbdkit/commit/8adf601835aee3779e278e13cae0489231960aee

Nice, I missed the pod file.

Nir