TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

New cache implementation and prefetch handing in mw/cache (#731)

Browse source 
* cache: add sharded cache implementation

Add Cache impl and a few tests. This cache is 256-way sharded, mainly
so each shard has it's own lock. The main cache structure is a readonly
jump plane into the right shard.

This should remove the single lock contention on the main lock and
provide more concurrent throughput - Obviously this hasn't been tested
or measured.

The key into the cache was made a uint32 (hash.fnv) and the hashing op
is not using strings.ToLower anymore remove any GC in that code path.

* here too

* Minimum shard size

* typos

* blurp

* small cleanups no defer

* typo

* Add freq based on Johns idea

* cherry-pick conflict resolv

* typo

* update from early code review from john

* add prefetch to the cache

* mw/cache: add prefetch

* remove println

* remove comment

* Fix tests

* Test prefetch in setup

* Add start of cache

* try add diff cache options

* Add hacky testcase

* not needed

* allow the use of a percentage for prefetch

If the TTL falls below xx% do a prefetch, if the record was popular.
Some other fixes and correctly prefetch only popular records.
This commit is contained in:
Miek Gieben 2017-06-13 12:39:10 -07:00 • committed by GitHub
parent b1efd3736e
commit e9eda7e7c8
23 changed files with 595 additions and 142 deletions
Download patch file Download diff file Expand all files Collapse all files

11
middleware/cache/item.go vendored
View file

@ -3,6 +3,7 @@ package cache
import (
"time"
"github.com/coredns/coredns/middleware/cache/freq"
"github.com/coredns/coredns/middleware/pkg/response"
"github.com/miekg/dns"
)
@ -18,6 +19,8 @@ type item struct {
origTTL uint32
stored time.Time
*freq.Freq
}
func newItem(m *dns.Msg, d time.Duration) *item {
@ -43,10 +46,12 @@ func newItem(m *dns.Msg, d time.Duration) *item {
i.origTTL = uint32(d.Seconds())
i.stored = time.Now().UTC()
i.Freq = new(freq.Freq)
return i
}
// toMsg turns i into a message, it tailers the reply to m.
// toMsg turns i into a message, it tailors the reply to m.
// The Authoritative bit is always set to 0, because the answer is from the cache.
func (i *item) toMsg(m *dns.Msg) *dns.Msg {
m1 := new(dns.Msg)
@ -67,9 +72,9 @@ func (i *item) toMsg(m *dns.Msg) *dns.Msg {
return m1
}
func (i *item) expired(now time.Time) bool {
func (i *item) ttl(now time.Time) int {
ttl := int(i.origTTL) - int(now.UTC().Sub(i.stored).Seconds())
return ttl < 0
return ttl
}
// setMsgTTL sets the ttl on all RRs in all sections. If ttl is smaller than minTTL