Replace global value of Stats by a DLS.key

CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Changed
 
+- Replace global value of Stats by a DLS.key (#404, @lyrm)
 - Lock files are now opened with O_CLOEXEC flag (#394, @vect0r-vicall)
 - Update to cmdliner.1.1.0 (#382, @MisterDA)
 - Mirage support: optional dependency to unix (#396, @art-w)

bench.Dockerfile

@@ -0,0 +1,11 @@
+FROM ocaml/opam:debian-ocaml-5.3
+RUN sudo ln -sf /usr/bin/opam-2.1 /usr/bin/opam
+RUN mkdir bench-dir && chown opam:opam bench-dir
+WORKDIR bench-dir
+RUN sudo chown opam .
+COPY *.opam ./
+RUN opam remote add origin https://github.com/ocaml/opam-repository.git && opam update
+RUN opam pin -yn --with-version=dev .
+RUN opam install -y --deps-only --with-test .
+COPY . ./
+ENTRYPOINT opam exec -- make bench

index-bench.opam

@@ -6,7 +6,7 @@ license: "MIT"
 homepage: "https://github.com/mirage/index"
 bug-reports: "https://github.com/mirage/index/issues"
 depends: [
-  "ocaml" {>= "4.03.0"}
+  "ocaml" {>= "5.0.0"}
   "cmdliner" {>= "1.1.0"}
   "dune" {>= "2.7.0"}
   "fmt"

index.opam

@@ -19,7 +19,7 @@ build: [
 ]
 
 depends: [
-  "ocaml"   {>= "4.08.0"}
+  "ocaml" {>= "5.0.0"}
   "dune"    {>= "2.7.0"}
   "optint"  {>= "0.1.0"}
   "repr"    {>= "0.6.0"}

src/stats.ml

@@ -31,10 +31,12 @@ let fresh_stats () =
     lru_misses = 0;
   }
 
-let stats = fresh_stats ()
-let get () = stats
+let fresh_stats_dls () = Domain.DLS.new_key (fun () -> fresh_stats ())
+let kstats = fresh_stats_dls ()
+let get () = Domain.DLS.get kstats
 
 let reset_stats () =
+  let stats = Domain.DLS.get kstats in
   stats.bytes_read <- 0;
   stats.nb_reads <- 0;
   stats.bytes_written <- 0;
@@ -48,23 +50,66 @@ let reset_stats () =
   stats.lru_hits <- 0;
   stats.lru_misses <- 0
 
-let incr_bytes_read n = stats.bytes_read <- stats.bytes_read + n
-let incr_bytes_written n = stats.bytes_written <- stats.bytes_written + n
-let incr_nb_reads () = stats.nb_reads <- succ stats.nb_reads
-let incr_nb_writes () = stats.nb_writes <- succ stats.nb_writes
-let incr_nb_merge () = stats.nb_merge <- succ stats.nb_merge
-let incr_nb_replace () = stats.nb_replace <- succ stats.nb_replace
-let incr_nb_sync () = stats.nb_sync <- succ stats.nb_sync
-let incr_nb_lru_hits () = stats.lru_hits <- succ stats.lru_hits
-let incr_nb_lru_misses () = stats.lru_misses <- succ stats.lru_misses
+let incr_nb_merge () =
+  let stats = Domain.DLS.get kstats in
+  stats.nb_merge <- succ stats.nb_merge
+
+let incr_nb_replace () =
+  let stats = Domain.DLS.get kstats in
+  stats.nb_replace <- succ stats.nb_replace
+
+let incr_nb_sync () =
+  let stats = Domain.DLS.get kstats in
+  stats.nb_sync <- succ stats.nb_sync
+
+let incr_nb_lru_hits () =
+  let stats = Domain.DLS.get kstats in
+  stats.lru_hits <- succ stats.lru_hits
+
+let incr_nb_lru_misses () =
+  let stats = Domain.DLS.get kstats in
+  stats.lru_misses <- succ stats.lru_misses
 
 let add_read n =
-  incr_bytes_read n;
-  incr_nb_reads ()
+  let stats = Domain.DLS.get kstats in
+  stats.bytes_read <- stats.bytes_read + n;
+  stats.nb_reads <- succ stats.nb_reads
 
 let add_write n =
-  incr_bytes_written n;
-  incr_nb_writes ()
+  let stats = Domain.DLS.get kstats in
+  stats.bytes_written <- stats.bytes_written + n;
+  stats.nb_writes <- succ stats.nb_writes
+
+let merge s1 s2 =
+  {
+    bytes_read = s1.bytes_read + s2.bytes_read;
+    nb_reads = s1.nb_reads + s2.nb_reads;
+    bytes_written = s1.bytes_written + s2.bytes_written;
+    nb_writes = s1.nb_writes + s2.nb_writes;
+    nb_merge = s1.nb_merge + s2.nb_merge;
+    merge_durations = s1.merge_durations @ s2.merge_durations;
+    nb_replace = s1.nb_replace + s2.nb_replace;
+    replace_durations = s1.replace_durations @ s2.replace_durations;
+    nb_sync = s1.nb_sync + s2.nb_sync;
+    time_sync = s1.time_sync +. s2.time_sync;
+    lru_hits = s1.lru_hits + s2.lru_hits;
+    lru_misses = s1.lru_misses + s2.lru_misses;
+  }
+
+let merge_in s2 =
+  let s1 = Domain.DLS.get kstats in
+  s1.bytes_read <- s1.bytes_read + s2.bytes_read;
+  s1.nb_reads <- s1.nb_reads + s2.nb_reads;
+  s1.bytes_written <- s1.bytes_written + s2.bytes_written;
+  s1.nb_writes <- s1.nb_writes + s2.nb_writes;
+  s1.nb_merge <- s1.nb_merge + s2.nb_merge;
+  s1.merge_durations <- s1.merge_durations @ s2.merge_durations;
+  s1.nb_replace <- s1.nb_replace + s2.nb_replace;
+  s1.replace_durations <- s1.replace_durations @ s2.replace_durations;
+  s1.nb_sync <- s1.nb_sync + s2.nb_sync;
+  s1.time_sync <- s1.time_sync +. s2.time_sync;
+  s1.lru_hits <- s1.lru_hits + s2.lru_hits;
+  s1.lru_misses <- s1.lru_misses + s2.lru_misses
 
 module Make (Clock : Platform.CLOCK) = struct
   let replace_timer = ref (Clock.counter ())
@@ -78,6 +123,7 @@ module Make (Clock : Platform.CLOCK) = struct
     if !nb_replace = sampling_interval then (
       let span = Clock.count !replace_timer in
       let average = Mtime.span_to_us span /. float_of_int !nb_replace in
+      let stats = Domain.DLS.get kstats in
       stats.replace_durations <- average :: stats.replace_durations;
       replace_timer := Clock.counter ();
       nb_replace := 0)
@@ -86,11 +132,13 @@ module Make (Clock : Platform.CLOCK) = struct
     let timer = Clock.counter () in
     f ();
     let span = Clock.count timer in
+    let stats = Domain.DLS.get kstats in
     stats.time_sync <- Mtime.span_to_us span
 
   let drop_head l = if List.length l >= 10 then List.tl l else l
 
   let add_merge_duration span =
     let span = Mtime.span_to_us span in
+    let stats = Domain.DLS.get kstats in
     stats.merge_durations <- drop_head stats.merge_durations @ [ span ]
 end

src/stats.mli

@@ -38,6 +38,8 @@ val incr_nb_replace : unit -> unit
 val incr_nb_sync : unit -> unit
 val incr_nb_lru_hits : unit -> unit
 val incr_nb_lru_misses : unit -> unit
+val merge : t -> t -> t
+val merge_in : t -> unit
 
 module Make (_ : Platform.CLOCK) : sig
   val start_replace : unit -> unit