dbuenzli / mtime Goto Github PK

View Code? Open in Web Editor NEW

33.0 6.0 22.0 165 KB

Monotonic wall-clock time for OCaml

Home Page: http://erratique.ch/software/mtime

License: ISC License

OCaml 80.80% C 12.40% JavaScript 6.79%

mtime's Issues

Mtime.span_{ns,s}_{of,to} are noisy

Remove the span_ prefix.

Windows compilation problem

Hello,

opam install mtime failed for me on windows (mingw64).

I tried to compile manually. For some reason I did not understood, I had to do the following to achieve compilation:

opam source mtime
cd mtime.1.2.0/
ocaml.exe pkg/pkg.ml build --pinned false --with-js_of_ocaml false
_build/sanitize.sh
ocaml.exe pkg/pkg.ml build --pinned false --with-js_of_ocaml false

And I solved my problem like this, but really do not understand:

opam source mtime
cd mtime.1.2.0/
ocaml.exe pkg/pkg.ml build --pinned false --with-js_of_ocaml false
_build/sanitize.sh
opam pin add mtime .

The first pkg build gives:

$ ocaml.exe pkg/pkg.ml build --pinned false --with-js_of_ocaml false
mkdir 'C:\OCaml64\home\MatthieuDubuget\mtime.1.2.0\_build'
Le chemin d’accès spécifié est introuvable.
''ocamlfind ocamlopt unix.cmxa -I 'C:/OCaml64/home/MatthieuDubuget/.opam/ocaml-variants.4.12.0+flambda+mingw64c/lib\ocamlbuild' 'C:/OCaml64/home/MatthieuDubuget/.opam/ocaml-variants.4.12.0+flambda+mingw64c/lib\ocamlbuild/ocamlbuildlib.cmxa' -linkpkg myocamlbuild.ml 'C:/OCaml64/home/MatthieuDubuget/.opam/ocaml-variants.4.12.0+flambda+mingw64c/lib\ocamlbuild/ocamlbuild.cmx' -o myocamlbuild.exe
SANITIZE: a total of 3 files that should probably not be in your source tree
  has been found. A script shell file
  "C:\\OCaml64\\home\\MatthieuDubuget\\mtime.1.2.0\\_build/sanitize.sh" is
  being created. Check this script and run it to remove unwanted files or use
  other options (such as defining hygiene exceptions or using the -no-hygiene
  option).
IMPORTANT: I cannot work with leftover compiled files.
ERROR: Leftover object files:
  File myocamlbuild.o in _build has suffix .o
ERROR: Leftover OCaml compilation files:
  File myocamlbuild.cmi in _build has suffix .cmi
  File myocamlbuild.cmx in _build has suffix .cmx
Exiting due to hygiene violations.
pkg.ml: [ERROR] cmd ["ocamlbuild" "-use-ocamlfind" "-classic-display" "-j" "4" "-tag" "debug"
     "-build-dir" "_build" "opam" "pkg/META" "CHANGES.md" "LICENSE.md"
     "README.md" "src/mtime.a" "src/mtime.cmxs" "src/mtime.cmxa"
     "src/mtime.cma" "src/mtime.cmx" "src/mtime.cmi" "src/mtime.mli"
     "src/mtime_top.a" "src/mtime_top.cmxs" "src/mtime_top.cmxa"
     "src/mtime_top.cma" "src/mtime_top.cmx" "src/mtime_top_init.ml"
     "doc/index.mld" "src-os/mtime_clock.a" "src-os/mtime_clock.cmxs"
     "src-os/mtime_clock.cmxa" "src-os/mtime_clock.cma"
     "src-os/mtime_clock.cmx" "src-os/mtime_clock.cmi"
     "src-os/mtime_clock.mli" "src-os/dllmtime_clock_stubs.dll"
     "src-os/libmtime_clock_stubs.a" "test-os/min_os.ml"]: exited with 1

and the sanitize.sh is:

#!/bin/sh
# File generated by ocamlbuild

cd 'C:\OCaml64\home\MatthieuDubuget\mtime.1.2.0'

rm -f _build/myocamlbuild.cmi
rm -f _build/myocamlbuild.cmx
rm -f _build/myocamlbuild.o
# Also clean the script itself
rm -f 'C:\OCaml64\home\MatthieuDubuget\mtime.1.2.0\_build/sanitize.sh'

Add a sensitive span pretty printer and toplevel support.

Should print units according to magnitude without too much floating point noise.

Add Mtime.period and raw interface

Raw interface.

support older versions of OCaml?

I could not find the reason why 4.03 is now needed.

Major API overhaul

Issue to discuss the upcoming api overhaul.

Dubious arithmetic

mtime_stubs.c calculates time in nanoseconds using:

(now.tv_sec - start.tv_sec) * 1000000000 + (now.tv_nsec - start.tv_nsec)

This does arithmetic at type time_t. If that's 32-bit, this will overflow in a few seconds. It should use 64-bit arithmetic explicitly, either with casts or temporaries, e.g:

(int64)(now.tv_sec - start.tv_sec) * (int64)1000000000 + 
    (int64)(now.tv_nsec - start.tv_nsec)

int64 time = now.tv_sec - start.tv_sec;
time *= 1000000000;
time += now.tv_nsec - start.tv_nsec

My system has a 64-bit time_t, so I haven't actually tested any of this :)

missing `@since` in documentation

It'd be nice to have @since 1.4 on, say, Mtime.Span.ms. It's useful when trying to write correct lower bounds for opam.

Conversion functions for timestamps

I'm trying to convert back and forth between Mtime.t and the timespec structure as described in the C bindings here: https://github.com/dsheets/ocaml-unix-time/blob/master/lib/time.mli .

Currently, to convert from Mtime.t to Timespec.t, I only found the following way:

let timespec_of_mtime mtime =
  let timestamp_ns = Mtime.to_uint64_ns mtime in
  let span = Mtime.Span.of_uint64_ns timestamp_ns in
  let sec = Mtime.Span.to_s span |> Int64.of_float in
  let sec_span = Mtime.Span.of_uint64_ns sec in
  let nsec = Mtime.Span.abs_diff span sec_span in
  Timespec.{ sec; nsec = Mtime.Span.to_uint64_ns nsec |> Int64.to_int }

...which seems convoluted, and I'm a bit scared of a loss of precision by going through floats.

Could there be some additional conversion functions from timestamps directly, and maybe also functions to get the fractional part of a timestamp / span? (for example the rust time stdlib seems to contain some of these).

bytecode support

I'm using mtime with ocamlopt but it would be nice to have mtime working with the toplevel or bytecode too.
Apparently it tries to load rt as a bytecode library and not the system librt.so:

$ ocamlc -version
4.02.3
$ ocamlfind ocamlc -package mtime.os x.ml -linkpkg  -verbose
Effective set of compiler predicates: pkg_mtime.os,autolink,byte
+ ocamlc.opt -verbose -I /home/edwin/.opam/4.02.3/lib/mtime/os /home/edwin/.opam/4.02.3/lib/mtime/os/mtime.cma x.ml
File "x.ml", line 1:
Error: Error on dynamically loaded library: dllrt.so: dllrt.so: cannot open shared object file: No such file or directory
ocamlc.opt returned with exit code 2

$ utop
[...]
utop # #require "mtime.os.top";;
Cannot load required shared library dllrt.                                                                                                                                  Reason: dllrt.so: dllrt.so: cannot open shared object file: No such file or directory.                                                                                      File "/home/edwin/.opam/4.02.3/lib/mtime/os/mtime_top_init.ml", line 1:                                                                                                     
Error: Reference to undefined global `Mtime'

Implement windows support

Using performance counters. PR welcome.

Compiling with -custom fails on ocaml_mtime_elapsed_ns

Using the min.ml example in the documentation.

ocamlfind ocamlc -package mtime.os -linkpkg -custom -o min.byte min.ml
/tmp/camlprimfa1abf-4fadb0.o:(.data+0x9d8): undefined reference to `ocaml_mtime_elapsed_ns'
clang-3.9: error: linker command failed with exit code 1 (use -v to see invocation)
File "min.ml", line 1:
Error: Error while building custom runtime system

mtime.1.2.0 fails to build with 5.1.0+trunk

When trying to compile mtime.1.2.0 with the latest 5.1.0+trunk, we observe the following error:

File "myocamlbuild.ml", line 1:
Error: /home/guest/sandmark/_opam/5.1.0+trunk/lib/ocamlbuild/ocamlbuild_plugin.cmx
       was built with -for-pack Ocamlbuild_pack, but the 
       current unit Myocamlbuild is not
Command exited with code 2.
pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-j' '4' '-tag' 'debug'
     '-build-dir' '_build' 'opam' 'pkg/META' 'CHANGES.md' 'LICENSE.md'
     'README.md' 'src/mtime.a' 'src/mtime.cmxa' 'src/mtime.cma'
     'src/mtime.cmx' 'src/mtime.cmi' 'src/mtime.mli' 'src/mtime_top.a'
     'src/mtime_top.cmxa' 'src/mtime_top.cma' 'src/mtime_top.cmx'
     'src/mtime_top_init.ml' 'doc/index.mld' 'src-os/mtime_clock.a'
     'src-os/mtime_clock.cmxa' 'src-os/mtime_clock.cma'
     'src-os/mtime_clock.cmx' 'src-os/mtime_clock.cmi'
     'src-os/mtime_clock.mli' 'src-os/dllmtime_clock_stubs.so'
     'src-os/libmtime_clock_stubs.a' 'test-os/min_os.ml']: exited with 10

What is a possible fix for the same?

Keeping a single, abstract, span would be more clever

Would avoid the double _ns, _s functions. Accessing concrete values should then go through conversion functions.

Files test.cmx and …/opam/mtime_clock.cmxa make inconsistent assumptions over interface Mtime_clock

The following fails in a 4.14 switch with flambda:

% cat test.ml
let _ = Mtime_clock.now_ns ()
% ocamlbuild -pkg mtime.clock -pkg mtime.clock.os test.native --
+ /home/fabian/.opam/4.14.0/bin/ocamlopt.opt -I /home/fabian/.opam/4.14.0/lib/mtime -I /home/fabian/.opam/4.14.0/lib/mtime/clock -I /home/fabian/.opam/4.14.0/lib/mtime/clock/os /home/fabian/.opam/4.14.0/lib/mtime/mtime.cmxa /home/fabian/.opam/4.14.0/lib/mtime/clock/os/mtime_clock.cmxa test.cmx -o test.native
File "_none_", line 1:
Error: Files test.cmx
       and /home/fabian/.opam/4.14.0/lib/mtime/clock/os/mtime_clock.cmxa
       make inconsistent assumptions over interface Mtime_clock
Command exited with code 2.

(removing -pkg mtime.clock fixes the issue, but it looks like there are some conflicting files in the installation, so I figured I'd raise it just in case)

Windows support

Seems that 0.8.3 broke windows support, see https://github.com/fdopen/opam-repository-mingw/blob/master/packages/mtime/mtime.0.8.3/files/mtime-0.8.3.patch for a possible fix.

/cc @fdopen

max_span = -1e-09s

I'm trying to convert OCaml durations (floats) to Mtime.Span.t, but having some trouble. Int64.of_float says:

If the truncated floating-point number is outside the range [Int64.min_int, Int64.max_int], no exception is raised, and an unspecified, platform-dependent integer is returned.

So I want to check the number is in-range before converting. But max_span seems to behave strangely:

utop # #require "fmt,mtime";;

utop # Mtime.Span.to_s (Mtime.Span.max_span);;
- : float = -1e-09

utop # Fmt.to_to_string Mtime.Span.pp Mtime.Span.max_span;;
- : string = "-0.001us"

What's the recommended way to convert a float in seconds to a span? Mtime's * operator says:

{b Warning.} Does not check for overflow or that [n] is positive.

So I guess I can't use that.

Add documentation on accessing Mtime_clock

It took me some trial and error and digging around to figure out how to build using the Mtime_clock module. In particular, if using the jbuilder build system, one has to list mtime.clock.os as a dependency, rather than the obvious mtime.clock. I think the same is true for oasis.

It would be helpful to new users if this detail were listed somewhere, perhaps straight in the README.md where Mtime_clock is first mentioned, and also in the API docs for that module.

Mtime.Span.to_uint64_s would be nice.

Would be nice to get a Span in seconds without having to go through a float.

Most network protocols talk in seconds, the most common operation is checking if something is too old on a second granularity. In this case the jitter is so high it doesn't matter if you round up or down.

Did I miss something or should I work on this ?

mtime fails to build with 4.14.0+trunk

I get the following error log when I try to build mtime with 4.14.0+trunk and dune.2.9.0

#=== ERROR while compiling mtime.1.2.0 ========================================#
# context     2.0.8 | linux/x86_64 | ocaml-variants.4.14.0+trunk | https://opam.ocaml.org#1fc79772
# path        ~/.opam/4.14.0+trunk/.opam-switch/build/mtime.1.2.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml pkg/pkg.ml build --pinned false --with-js_of_ocaml false
# exit-code   1
# env-file    ~/.opam/log/mtime-2324156-d2c37b.env
# output-file ~/.opam/log/mtime-2324156-d2c37b.out
### output ###
# [...]
# Command exited with code 2.
# pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-j' '4' '-tag' 'debug'
#      '-build-dir' '_build' 'opam' 'pkg/META' 'CHANGES.md' 'LICENSE.md'
#      'README.md' 'src/mtime.a' 'src/mtime.cmxs' 'src/mtime.cmxa'
#      'src/mtime.cma' 'src/mtime.cmx' 'src/mtime.cmi' 'src/mtime.mli'
#      'src/mtime_top.a' 'src/mtime_top.cmxs' 'src/mtime_top.cmxa'
#      'src/mtime_top.cma' 'src/mtime_top.cmx' 'src/mtime_top_init.ml'
#      'doc/index.mld' 'src-os/mtime_clock.a' 'src-os/mtime_clock.cmxs'
#      'src-os/mtime_clock.cmxa' 'src-os/mtime_clock.cma'
#      'src-os/mtime_clock.cmx' 'src-os/mtime_clock.cmi'
#      'src-os/mtime_clock.mli' 'src-os/dllmtime_clock_stubs.so'
#      'src-os/libmtime_clock_stubs.a' 'test-os/min_os.ml']: exited with 10

Clarify/document sleep behaviour

E.g. mach_absolute_time doesn't take into account if the OS what put to sleep. I believe this is also the case for CLOCK_MONOTONIC.

Add time span constants

This is somewhat redundant with Mtime.{ns,s}_of functions but it can lead to cleaner code. For example adding three days:

let t' = t +. (3. *. Mtime.day_s)
(* vs *)
let t' = t +. (Mtime.s_of `Day 3.)

Consider deprecating floating point durations and add uint64 duration constants

See e.g. #27

/usr/bin/ld: cannot find -lmtime_clock_stubs

On various systems (including x86_32), mtime fails to link. It's easy to reproduce with dune by simply depending on mtime.clock.os, but it fails with ocamlfind too:

$ touch main.ml
$ ocamlfind ocamlc -output-complete-exe -linkpkg -package mtime.clock.os main.ml
/usr/bin/ld: cannot find -lmtime_clock_stubs
collect2: error: ld returned 1 exit status
File "main.ml", line 1:
Error: Error while building custom runtime system

I tried to run mtime's own tests, but:

$ ocaml pkg/pkg.ml test
pkg.ml: No tests to run.

Other packages with C stubs (e.g. cstruct) do work.

(@mseri reported this as an Eio bug at ocaml-multicore/eio#407, but it doesn't seem like it has much to do with Eio)

Cross-compilation support

Something like this patch would help cross-compilation:

--- a/myocamlbuild.ml 2018-03-04 11:03:00.253554294 +0000
+++ b/myocamlbuild.ml 2018-03-04 11:03:25.285553267 +0000
@@ -2,7 +2,11 @@
 open Ocamlbuild_plugin
 open Command

-let os = Ocamlbuild_pack.My_unix.run_and_read "uname -s"
+let os =
+  try
+    Sys.getenv "MTIME_OS"
+  with Not_found ->
+    Ocamlbuild_pack.My_unix.run_and_read "uname -s"

 let system_support_lib = match os with
 | "Linux\n" -> [A "-cclib"; A "-lrt"]

Related to #2.

Expose the absolute representation ?

Currently, only the result of subtracting absolute monotonic time stamps is exposed and not their absolute values. One usage scenario that this prevents is for a program to be able to measure the monotonic amount of time that occured between two runs of the program itself.

However the only function used in the backends that provides us a documented guarantee to be able to do that seems to be clock_gettime (it gives the guarantee that the time stamps are system wide starting from an epoch cast in stone at startup time) and you'd still need a way to be able to detect if the operating system hasn't rebooted meanwhile. For sure JavaScript's performance.now () doesn't give us that as it seems to start from zero once the page load.

It seems that this would be better solved by looking up some kind of TAI clock (if only OSes would provide us with that).

dbuenzli / mtime Goto Github PK

mtime's Issues

Recommend Projects

Recommend Topics

Recommend Org