Those settings shouldn't make a big difference in how the number of
connections scale up, though. There is a theoretical maximum rate limit
for creating new connections as each socket is supposed to sit in
TIME_WAIT for a packet round-trip time to ensure that nothing
outstanding will collide with that socket number when it is reused for
the same IP address. Maybe your test is hitting that limit. Can you
set SO_REUSEADDR?
On 2/25/2011 12:25 PM, Sean Cribbs wrote:
Now you're talking about tweaking kernel-level settings -- something well
outside my expertise (although TCP slow-start comes to mind). That said, it's
kind of hard not to use TCP if you want a reliable connection, warts and all.
Sean Cribbs<s...@basho.com>
Developer Advocate
Basho Technologies, Inc.
http://basho.com/
On Feb 25, 2011, at 1:06 PM, Wilson MacGyver wrote:
any advise to solve this?
On Fri, Feb 25, 2011 at 1:05 PM, Sean Cribbs<s...@basho.com> wrote:
Yes, the majority of the cost is probably in TCP setup. That pain is happening at the TCP
stack level, not in Erlang. It's actually really cheap and easy to spawn a new process
in Erlang, so there's no reason to have "standby workers", especially when they
don't need to maintain state between requests.
Sean Cribbs<s...@basho.com>
Developer Advocate
Basho Technologies, Inc.
http://basho.com/
On Feb 25, 2011, at 12:45 PM, Wilson MacGyver wrote:
I've tried it, it didn't have much impact. A bit more info on how I'm
doing the test.
I'm using apachebench. I purposely have it grab the same key/value over and over
again.
if I use concurrent connection of 10, 1000 requests each. 50% of the
request complets
within 7ms, longest request is 38ms. this is quite good.
now, if I increase the concurrent connection to 100, 50% of the
request complets at 77ms.
it "feels" like a paying for startup cost of connection problem to me.
Is there a way to purposely
startup riak with a bunch of standby workers, or something to that effect?
On Fri, Feb 25, 2011 at 11:37 AM, Sean Cribbs<s...@basho.com> wrote:
You can disable Nagle on the riak side (at least on 0.14 and later). Put this
in the riak_core section of app.config:
{disable_http_nagle, true}
Sean Cribbs<s...@basho.com>
Developer Advocate
Basho Technologies, Inc.
http://basho.com/
On Feb 25, 2011, at 9:33 AM, Wilson MacGyver wrote:
TCP_NODELAY is something you'd set when you use the socket API call,
not a global tuning setting on the OS as I recall.
On Fri, Feb 25, 2011 at 9:28 AM, Nico Meyer<nico.me...@adition.com> wrote:
Whenever I see latencies which are roughly multiples of 40ms it screams
to me 'nagle algorithm'. I have seen this so often now, that the first
thing I check is, if the TCP_NODELAY option is set on the TCP socket on
both ends.
--
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