Ema has uploaded a new change for review. (
https://gerrit.wikimedia.org/r/393227 )
Change subject: WIP: cache: size-based cutoff for exp caching policy
......................................................................
WIP: cache: size-based cutoff for exp caching policy
- Limit the exp caching policy to Varnish 5 (v4 has no HFM)
- Unconditionally return HFM for exp
- Add a size-based HFP cutoff
Bug: T144187
Change-Id: I5a326e128153af9e3f21840eaf53164a4eb586d6
---
M modules/varnish/templates/vcl/wikimedia-common.inc.vcl.erb
M modules/varnish/templates/vcl/wikimedia-frontend.vcl.erb
2 files changed, 18 insertions(+), 6 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/operations/puppet
refs/changes/27/393227/1
diff --git a/modules/varnish/templates/vcl/wikimedia-common.inc.vcl.erb
b/modules/varnish/templates/vcl/wikimedia-common.inc.vcl.erb
index a4d32e0..bcbd68c 100644
--- a/modules/varnish/templates/vcl/wikimedia-common.inc.vcl.erb
+++ b/modules/varnish/templates/vcl/wikimedia-common.inc.vcl.erb
@@ -447,6 +447,22 @@
return (deliver);
<%- end -%>
}
+
+<% if @varnish_version == 5 && @vcl_config.fetch("admission_policy", "nhw") ==
"exp" -%>
+ // XXX: this should most likely not be defined here, as the exp policy
need
+ // to be applied on the frontend layer only
+
+ // We want to apply the "exp" caching policy only to objects with CL
below
+ // 10M (but present). The "exp" caching policy is defined in
+ // wikimedia-frontend.vcl.erb, but the logic below can not be added
there
+ // because by returning HFP we would skip calling various VCL
subroutines such
+ // as cluster_fe_backend_response_early.
+ if (beresp.status == 200 && bereq.http.X-CDIS == "miss"
+ && std.integer(beresp.http.Content-Length, 0) >= 1024 * 1024 *
10) {
+ // HFP
+ return(pass(120s));
+ }
+<%- end -%>
}
// call just before wm_common_xcache_deliver, but only in vcl_deliver, not
vcl_synth
diff --git a/modules/varnish/templates/vcl/wikimedia-frontend.vcl.erb
b/modules/varnish/templates/vcl/wikimedia-frontend.vcl.erb
index a3f5826..7ea9c50 100644
--- a/modules/varnish/templates/vcl/wikimedia-frontend.vcl.erb
+++ b/modules/varnish/templates/vcl/wikimedia-frontend.vcl.erb
@@ -2,7 +2,7 @@
vcl 4.0;
-<% if @vcl_config.fetch("admission_policy", "nhw") == "exp" -%>
+<% if @varnish_version == 5 && @vcl_config.fetch("admission_policy", "nhw") ==
"exp" -%>
// Includes for Exp cache admission policy, admission probability exponentially
// decreasing with size. See vcl_backend_response. T144187
C{
@@ -358,7 +358,7 @@
if (beresp.status == 503 && bereq.retries == 0 && bereq.method ~
"^(GET|HEAD|OPTIONS|PUT|DELETE)$") {
return(retry);
}
-<% if @vcl_config.fetch("admission_policy", "nhw") == "exp" -%>
+<% if @varnish_version == 5 && @vcl_config.fetch("admission_policy", "nhw") ==
"exp" -%>
if (beresp.status == 200 && bereq.http.X-CDIS == "miss") {
C{
const struct gethdr_s hdr = { HDR_BERESP, "\017Content-Length:" };
@@ -391,12 +391,8 @@
// If admission test succeeds, mark as uncacheable
if (admissionprob < urand) {
- <%- if @varnish_version == 5 -%>
// HFM with ttl=67 to avoid stalling
VRT_l_beresp_ttl(ctx,67);
- <%- else -%>
- VRT_l_beresp_ttl(ctx,0);
- <%- end -%>
VRT_l_beresp_uncacheable(ctx,1);
}
}
--
To view, visit https://gerrit.wikimedia.org/r/393227
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I5a326e128153af9e3f21840eaf53164a4eb586d6
Gerrit-PatchSet: 1
Gerrit-Project: operations/puppet
Gerrit-Branch: production
Gerrit-Owner: Ema <e...@wikimedia.org>
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