On 2015-04-22 4:49 PM, Ulrich Windl wrote: >>>> Geoff Swan <gsw...@bigpond.net.au> schrieb am 21.04.2015 um 23:19 in >>>> Nachricht > <5536bec9.3040...@bigpond.net.au>: > >> On 2015-04-22 6:04 AM, Howard Chu wrote: >>> Brian Reichert wrote: >>>> On Tue, Apr 21, 2015 at 08:23:31AM -0700, Quanah Gibson-Mount wrote: >>>>> --On Tuesday, April 21, 2015 11:54 AM -0400 Brian Reichert >>>>> <reich...@numachi.com> wrote: >>>>>> What does your config file look like? >>>>>> >>>>>> In particular, what does this setting look like for you: >>>>>> >>>>>> # Threads - four per CPU >>>>>> threads 8 >>>>> According to his summary, he's using 48 threads. >>>> Thanks for pointing that out; I should finish my coffee before >>>> posting. :) >>>> >>>>> 4 per CPU/core was a good >>>>> rule of thumb with bdb/hdb. So far in playing with back-mdb, it's >>>>> seemed >>>>> closer to 2 per CPU/core for me in benchmarking. >> Interesting. What is the relationship between the number of threads and >> the number of concurrent bind operations? >> If I have, say, 500 clients wanting access to perform simple >> authentication/bind and perform some read/write operation, how is this >> usually handled within slapd? >> >>>> Useful to note. Has this detail ended up in any docs yet? >>> No, nor should it. Performance depends on system environment and >>> workload - the right value is one that each site must discover for >>> themselves in their own deployment. >>> >> Are there any clues about key factors affecting this? Linux, in this >> case, has vm.swappiness set to 10, vm.dirty_ratio at 12 and >> vm.dirty_background at 3. However I've noticed that when dirty pages are >> flushed to disc, the system stalls. And that operation appears to take a >> relatively long time. Disc write speed should be close to 130MB/s (file >> copy, dd test etc) however it appears to be much slower than this with >> the page flush. > Did you try NOT tuning those? A swapped in-memory database is not the thing > you usually want. > Swappiness for an out-of-the-box kernel was 60, which sounds way too high. So I reduced it to 10.
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