Merge pull request PelicanPlatform#1654 from turetske/cache-prefix-co…

…nfigurable Made the xrootd cache prefetch variable configurable via a pelican va…
jhiemstrawisc · Nov 12, 2024 · dbb8da6 · dbb8da6
2 parents abb1eec + b66c3e6
commit dbb8da6
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Showing 6 changed files with 15 additions and 1 deletion.
diff --git a/config/resources/defaults.yaml b/config/resources/defaults.yaml
@@ -65,6 +65,7 @@ Cache:
   SelfTestInterval: 15s
   LowWatermark: 90
   HighWaterMark: 95
+  BlocksToPrefetch: 0
 LocalCache:
   HighWaterMarkPercentage: 95
   LowWaterMarkPercentage: 85

diff --git a/docs/parameters.yaml b/docs/parameters.yaml
@@ -1240,6 +1240,15 @@ type: bool
 default: false
 components: ["cache"]
 ---
+name: Cache.BlocksToPrefetch
+description: |+
+  The number of 128 kilobyte blocks the cache will read ahead when recieving requests. This will put the data in the cache
+  potentially before it is needed and reduce the latency to the client when a request is made. However, it can also cause
+  many extra requests to an origin and potentially overload it when unnessesary. As such, this is turned off by default.
+type: int
+default: 0
+components: ["cache"]
+---
 ############################
 #  Director-level configs  #
 ############################

diff --git a/param/parameters.go b/param/parameters.go
diff --git a/param/parameters_struct.go b/param/parameters_struct.go
diff --git a/xrootd/resources/xrootd-cache.cfg b/xrootd/resources/xrootd-cache.cfg
@@ -53,7 +53,7 @@ pfc.trace info
 xrootd.tls all
 xrd.network nodnr
 pfc.blocksize 128k
-pfc.prefetch 20
+pfc.prefetch {{.Cache.BlocksToPrefetch}}
 pfc.writequeue 16 4
 pfc.ram 4g
 pfc.diskusage {{if .Cache.LowWatermark}}{{.Cache.LowWatermark}}{{else}}0.90{{end}} {{if .Cache.HighWaterMark}}{{.Cache.HighWaterMark}}{{else}}0.95{{end}} purgeinterval 300s

diff --git a/xrootd/xrootd_config.go b/xrootd/xrootd_config.go
@@ -117,6 +117,7 @@ type (
 		MetaLocations                    []string
 		LocalRoot                        string
 		PSSOrigin                        string
+		BlocksToPrefetch                 int
 		Concurrency                      int
 		X509ClientAuthenticationPrefixes []string
 	}