Hi Seth Do you have a tool that helps you measure the cache hit resolution time?
On Wed, 26 Nov 2025, 15:34 sir izake, <[email protected]> wrote: > Thanks Seth. > > I'll make the adjustments and monitor performance. > > > > On Wed, Nov 26, 2025 at 12:37 PM Seth Van Buren < > [email protected]> wrote: > >> I think you missed the point. See: >> https://nlnetlabs.nl/documentation/unbound/howto-optimise/ >> >> Set >> *-slabs >> to a power of 2 close to the >> num-threads >> value. Do this for >> msg-cache-slabs >> , >> rrset-cache-slabs >> , >> infra-cache-slabs >> and >> key-cache-slabs >> . This reduces lock contention. >> >> I service several hundred thousands of simultaneous clients with 10,000s >> queries per second on only 12 threads. Cache response time is less than >> 1ms, average response time is < 10ms. My hosts (I have 3 of them) have 16 >> threads/cores each, I leave 4 threads to do some server busy work like >> stats and logs collection. More threads doesn’t always mean better >> performance and in your case since your slab count is low you’re going to >> have a lot of lock contention. >> >> Cheers >> >> >> *From: *sir izake <[email protected]> >> *Date: *Wednesday, 26 November 2025 at 7:35 pm >> *To: *Seth Van Buren <[email protected]> >> *Cc: *[email protected] <[email protected]> >> *Subject: *Re: How to measure cache hit resolution time in unbound 1.24.1 >> >> Hi Seth >> >> The server is dedicated for this purpose hence the high number of threads >> >> below configs are in place: >> >> num-queries-per-thread: 4096 >> msg-cache-size: 10G >> rrset-cache-size: 20G >> key-cache-size: 1G >> >> Thank you >> >> On Wed, Nov 26, 2025 at 3:34 AM Seth Van Buren < >> [email protected]> wrote: >> >> Your thread should be equal to or lower than the number of slabs. >> >> The thread count seems extremely high, you should not need so many. You >> should set num-queries-per-thread. Try 16384 >> >> Can you also paste your memory settings and Cache settings? >> >> >> *From: *sir izake <[email protected]> >> *Date: *Tuesday, 25 November 2025 at 8:08 pm >> *To: *Seth Van Buren <[email protected]> >> *Cc: *[email protected] <[email protected]> >> *Subject: *Re: How to measure cache hit resolution time in unbound 1.24.1 >> >> Hi Seth >> >> num-threads: 64 >> msg-cache-slabs: 32 >> rrset-cache-slabs: 32 >> infra-cache-slabs: 32 >> key-cache-slabs: 32 >> ratelimit-slabs: 32 >> ip-ratelimit-slabs: 32 >> >> The physical server is a dell 640 with specs below >> >> hw.ncpu: 104 >> hw.model: Intel(R) Xeon(R) Gold 6230R CPU @ 2.10GHz >> >> Thank you >> Isaac >> >> >> On Tue, Nov 25, 2025 at 5:13 AM Seth Van Buren < >> [email protected]> wrote: >> >> Home many cores/slabs are you using? >> >> *From: *Unbound-users <[email protected]> on >> behalf of sir izake via Unbound-users <[email protected]> >> *Date: *Tuesday, 25 November 2025 at 2:51 pm >> *To: *[email protected] <[email protected]> >> *Subject: *How to measure cache hit resolution time in unbound 1.24.1 >> >> Hi >> >> I have installed unbound 1.24.1 on FreeBSD 14.3 OS. My cache hit rate is >> 76% with over 20% coming through recursive replies. >> >> The median time for recursive replies is 440ms while the avg is 520ms. >> >> This setup has been running for over 72hrs. I expect stats to improve but >> that is not happening. >> >> Just wanted to find out if there is a way to measure the cache hit >> resolution time in a dashboard? >> >> Can I do anything to improve cache hit ratio? >> >> Can I also improve the recursive reply time? >> >> I am using unbound_exporter to monitor stats in grafana >> >> My configs have been adjusted as follows: >> rrset-cache-size: 20G >> msg-cache-size: 10G >> cache-min-ttl: 1800 >> >> I am using the root hint files directly on the server for recursive >> lookup and not forwarding to any public resolver >> >> Thank you >> >> Regards, >> Isaac >> >> >>
