On 22/11/17 13:37, Marco Neumann wrote:
On Wed, Nov 22, 2017 at 2:15 PM, Andy Seaborne <[email protected]> wrote:
On 22/11/17 10:55, Marco Neumann wrote:
i have noticed that a single fuseki instance spans quite a number of
worker process (~32-35) on one of our root servers ( x86_64 GNU/Linux)
with 8 cores and 128gb ram + ssd.
does jena fuseki /tdb take full advantage of the extras cores on full
load with these workers?
Fuseki runs one thread per request (nearly - sorting can us multiple
threads).
that was my reading of what goes on in process viewer, ~30 is the
number of workers after a fresh start and idle (no requests) .
Jetty, as web app container, starts all threads on startup and they go
into somekind of pool - threads are not created per request (Fuseki does
not create threads.) If they are not used, they are just sitting around
idle with a stack area.
A request comes in and the Fuseki servlet filter sees if it is Fuseki
related and if so, sends it (by java menthod call) to a dispatch
servlet, that pokes around to see what it is and sends it on to the
right servlet (again, by java call, not Servlet.service)
I only know this as I had to look Monday and yesterday when
investigating what it would take for custom services.
Andy
It would be nice to execute with more threads but the time to do this ...
It's jetty starting the threads.
(32 seems a lot but maybe Jetty is allocating based on core+HT count)
indeed, but it's actually one of our "smaller" test machines and
performance is quite good so far.
Andy
On Wed, Nov 22, 2017 at 11:22 AM, David Moss <[email protected]> wrote:
Upgrades are application specific. You need to look at the logs for your
current system and see if processor is maxing out of memory is swapping out
to disk too much. 2GB RAM looks a bit small but that is irrelevant if your
processor is at 100% all the time. You might also consider your disk access
time. Faster disks might be a better buy if your processor and RAM look OK.
David Moss
________________________________
From: John Sanders <[email protected]>
Sent: Wednesday, November 22, 2017 10:40:38 AM
To: [email protected]
Subject: Advice on hardware upgrade
Hi, I'm running a Fuseki server on a rather small server. I'm willing to
upgrade it a little bit (since it's handling a lot of requests) so I was
wondering which single component I could upgrade to get the best possible
return. This I suppose boils down to either more RAM or a better CPU.
Currently the server is an old Pentium4 3GHz with 2gb of RAM, so if I have
some money to spend on it, would I be better buying more RAM or a better
CPU? In the second case (a better CPU), would Fuseki benefit more from a
faster one (higher frequency) or one with more cores/threads (I assume
Fuseki is a multi-threaded application)? Thank you all.
