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02/04: store: 'mcached' users can specify a cache ID.
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guix-commits |
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Subject: |
02/04: store: 'mcached' users can specify a cache ID. |
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Date: |
Wed, 18 May 2022 18:05:19 -0400 (EDT) |
civodul pushed a commit to branch master
in repository guix.
commit ba6ba1a5af4aae36f9abc22ca5e6128f49576c9d
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Thu May 12 23:16:11 2022 +0200
store: 'mcached' users can specify a cache ID.
Users of 'mcached' can now specify a cache ID; furthermore, the cache
hit rate is automatically recorded for all the caches accessed with
'mcached'.
* guix/store.scm (%max-store-connection-caches)
(%store-connection-cache-names): New variables.
(recorder-for-cache): New procedure.
(record-cache-lookup!): Add 'cache-id' parameter and rewrite in terms of
'recorder-for-cache'.
(lookup-cached-object): Add 'cache-id' parameter and honor it.
(%mcached): Add #:cache parameter and honor it.
(mcached): Add '=>' keyword and corresponding clauses.
---
guix/store.scm | 67 ++++++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 54 insertions(+), 13 deletions(-)
diff --git a/guix/store.scm b/guix/store.scm
index 1d176fb99d..220901f6ce 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012-2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Jan Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2019, 2020 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2020 Florian Pelz <pelzflorian@pelzflorian.de>
@@ -1793,6 +1793,14 @@ This makes sense only when the daemon was started with
'--cache-failures'."
;; the 'caches' vector of <store-connection>.
(define %store-connection-caches (make-atomic-box 0))
+(define %max-store-connection-caches
+ ;; Maximum number of caches returned by 'allocate-store-connection-cache'.
+ 32)
+
+(define %store-connection-cache-names
+ ;; Mapping of cache ID to symbol.
+ (make-vector %max-store-connection-caches))
+
(define (allocate-store-connection-cache name)
"Allocate a new cache for store connections and return its identifier. Said
identifier can be passed as an argument to "
@@ -1800,7 +1808,9 @@ identifier can be passed as an argument to "
(let ((previous (atomic-box-compare-and-swap! %store-connection-caches
current (+ current 1))))
(if (= previous current)
- current
+ (begin
+ (vector-set! %store-connection-cache-names current name)
+ current)
(loop current)))))
(define %object-cache-id
@@ -1926,16 +1936,37 @@ whether the cache lookup was a hit, and the actual
cache (a vhash)."
(lambda (x y)
#t)))
-(define record-cache-lookup!
- (cache-lookup-recorder "object-cache" "Store object cache"))
-
-(define-inlinable (lookup-cached-object object keys vhash-fold*)
- "Return the cached object in the store connection corresponding to OBJECT
+(define recorder-for-cache
+ (let ((recorders (make-vector %max-store-connection-caches)))
+ (lambda (cache-id)
+ "Return a procedure to record lookup stats for CACHE-ID."
+ (match (vector-ref recorders cache-id)
+ ((? unspecified?)
+ (let* ((name (symbol->string
+ (vector-ref %store-connection-cache-names cache-id)))
+ (description
+ (string-titlecase
+ (string-map (match-lambda
+ (#\- #\space)
+ (chr chr))
+ name))))
+ (let ((proc (cache-lookup-recorder name description)))
+ (vector-set! recorders cache-id proc)
+ proc)))
+ (proc proc)))))
+
+(define (record-cache-lookup! cache-id value cache)
+ "Record the lookup of VALUE in CACHE-ID, whose current value is CACHE."
+ (let ((record! (recorder-for-cache cache-id)))
+ (record! value cache)))
+
+(define-inlinable (lookup-cached-object cache-id object keys vhash-fold*)
+ "Return the object in store cache CACHE-ID corresponding to OBJECT
and KEYS; use VHASH-FOLD* to look for OBJECT in the cache. KEYS is a list of
additional keys to match against, and which are compared with 'equal?'.
Return #f on failure and the cached result otherwise."
(lambda (store)
- (let* ((cache (store-connection-cache store %object-cache-id))
+ (let* ((cache (store-connection-cache store cache-id))
;; Escape as soon as we find the result. This avoids traversing
;; the whole vlist chain and significantly reduces the number of
@@ -1949,40 +1980,50 @@ Return #f on failure and the cached result otherwise."
result))))
#f object
cache))))
- (record-cache-lookup! value cache)
+ (record-cache-lookup! cache-id value cache)
(values value store))))
(define* (%mcached mthunk object #:optional (keys '())
#:key
+ (cache %object-cache-id)
(vhash-cons vhash-consq)
(vhash-fold* vhash-foldq*))
"Bind the monadic value returned by MTHUNK, which supposedly corresponds to
OBJECT/KEYS, or return its cached value. Use VHASH-CONS to insert OBJECT into
the cache, and VHASH-FOLD* to look it up."
- (mlet %store-monad ((cached (lookup-cached-object object keys
+ (mlet %store-monad ((cached (lookup-cached-object cache object keys
vhash-fold*)))
(if cached
(return cached)
(>>= (mthunk)
(lambda (result)
(cache-object-mapping object keys result
+ #:cache cache
#:vhash-cons vhash-cons))))))
(define-syntax mcached
- (syntax-rules (eq? equal?)
+ (syntax-rules (eq? equal? =>)
"Run MVALUE, which corresponds to OBJECT/KEYS, and cache it; or return the
value associated with OBJECT/KEYS in the store's object cache if there is
one."
- ((_ eq? mvalue object keys ...)
+ ((_ eq? (=> cache) mvalue object keys ...)
(%mcached (lambda () mvalue)
object (list keys ...)
+ #:cache cache
#:vhash-cons vhash-consq
#:vhash-fold* vhash-foldq*))
- ((_ equal? mvalue object keys ...)
+ ((_ equal? (=> cache) mvalue object keys ...)
(%mcached (lambda () mvalue)
object (list keys ...)
+ #:cache cache
#:vhash-cons vhash-cons
#:vhash-fold* vhash-fold*))
+ ((_ eq? mvalue object keys ...)
+ (mcached eq? (=> %object-cache-id)
+ mvalue object keys ...))
+ ((_ equal? mvalue object keys ...)
+ (mcached equal? (=> %object-cache-id)
+ mvalue object keys ...))
((_ mvalue object keys ...)
(mcached eq? mvalue object keys ...))))