4:19 a.m.
On Mon, Sep 05, 2022 at 02:10:36PM +0200, Laszlo Ersek wrote:
On 09/03/22 00:14, Eric Blake wrote:
> This proves that the stat counters increment as desired, as well as
> proving that our RUInt32 generator type works.
How is this related to RUint32?
Typo in the commit message; this should be RUInt64. Oh well, the
commit is already in.
>
> This commit is also a showcase of whether I can do 64-bit math in
> various languages (C's terseness in 'a == b + (c > d)' is annoying
to
> replicate in languages that don't like playing fast and loose with
> types). :)
I don't understand; please elaborate.
Sure. In C, uint64_t == uint64_t + bool is legal; making for a nice
terse expression.
> +++ b/python/t/620-stats.py
> +# Stats are still readable after the connection closes; we
don't know if
> +# the server sent reply bytes to our NBD_CMD_DISC, so don't insist on it.
> +h.shutdown()
> +
> +bs3 = h.stats_bytes_sent()
> +cs3 = h.stats_chunks_sent()
> +br3 = h.stats_bytes_received()
> +cr3 = h.stats_chunks_received()
> +
> +assert bs3 > bs2
> +assert cs3 == cs2 + 1
> +assert br3 >= br2
> +assert cr3 == cr2 + (br3 > br2)
And in python.
> +++ b/ocaml/tests/test_620_stats.ml
> + (* Stats are still readable after the connection closes; we don't know if
> + * the server sent reply bytes to our NBD_CMD_DISC, so don't insist on it.
> + *)
> + NBD.shutdown nbd;
> +
> + let bs3 = NBD.stats_bytes_sent nbd in
> + let cs3 = NBD.stats_chunks_sent nbd in
> + let br3 = NBD.stats_bytes_received nbd in
> + let cr3 = NBD.stats_chunks_received nbd in
> + let fudge = if cr2 = cr3 then 0L else 1L in
> + assert (bs3 > bs2);
> + assert (cs3 = (Int64.succ cs2));
> + assert (br3 >= br2);
> + assert (cr3 = (Int64.add cr2 fudge))
Not so in OCaml, where + isn't even polymorphic to int64, so I have to
break out manual calls to Int64.XXX methods. Here, I went with a
helper variable 'fudge'.
> +++ b/golang/libnbd_620_stats.go
> + /* Stats are still readable after the connection closes; we don't know if
> + * the server sent reply bytes to our NBD_CMD_DISC, so don't insist on it.
> + */
> + err = h.Shutdown(nil)
> + if err != nil {
> + t.Fatalf("%s", err)
> + }
> +
> + bs3, err := h.StatsBytesSent()
> + if err != nil {
> + t.Fatalf("%s", err)
> + }
> + cs3, err := h.StatsChunksSent()
> + if err != nil {
> + t.Fatalf("%s", err)
> + }
> + br3, err := h.StatsBytesReceived()
> + if err != nil {
> + t.Fatalf("%s", err)
> + }
> + cr3, err := h.StatsChunksReceived()
> + if err != nil {
> + t.Fatalf("%s", err)
> + }
> + slop := uint64(1)
> + if br2 == br3 {
> + slop = uint64(0)
> + }
> +
> + if bs3 <= bs2 {
> + t.Fatalf("unexpected value for bs3")
> + }
> + if cs3 != cs2 + 1 {
> + t.Fatalf("unexpected value for cs3")
> + }
> + if br3 < br2 {
> + t.Fatalf("unexpected value for br3")
> + }
> + if cr3 != cr2 + slop {
> + t.Fatalf("unexpected value for cr3")
> + }
Nor in Go, where you can't even do uint64(bool), but HAVE to use an
'if' statement to populate 'slop' with the correct value. Hmm, maybe
I should have used the same variable name between OCaml and Go,
instead of 'slop'/'fudge'; oh well. (And Go is painfully verbose in
the amount of boilerplate formatting it requires, compared to the
other languages; although I will be the first to admit that I'm
probably not an idiomatic Go coder)
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
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