On 2016-04-21 11:30, Tim Hughes wrote:
On 2016-04-21 03:57, Glyph wrote:
On Apr 20, 2016, at 10:37, Tim Hughes <thug...@thegoldfish.org>
wrote:
Hi All,
I have a latency sensitive application that gets affected when it is
moved between cores or the system has to wake from idling.
Can you explain "gets affected" in more detail? If moving between
cores is the issue, could you set its CPU affinity?
That is exactly what I would do with a physical machine but
unfortunately where I need to use it is in china and I only have xen
virtual machines available. I know this isn't the best situation but
unfortunately that is all I can get in these locations.
I would like to run the thread in as tight a loop as possible and to
do this i need to cause epollreactor to busyspin on receiving data.
I am very curious about your application now :)
We are using it to test the performance of streaming financial market
data over different CDN providers to different cities around the
world. Currently trying to jump through the hoops to be able to
opensource it and stick it on github. It isn't that exciting, it is
basically a modified LineReceiver with the delimiter set to \x01 and
the messages are key=value pairs at a peak rate of approx 130000 pairs
per second
https://en.wikipedia.org/wiki/Financial_Information_eXchange
Hoops have been jumped and it is on github at
https://github.com/LMAX-Exchange/txfixclient
I have worked out how to do it by editing the twisted code directly
by hard coding the value of `timeout` to be 0 at this location in the
code
https://github.com/twisted/twisted/blob/f074ba3d5083aa1503abcf194aece327e7f84805/twisted/internet/epollreactor.py#L370
Is it possible to actually set this on the reactor in a more sensible
way so I don't need to patch the twisted codebase. ? Below is
basically what I am doing.
You can achieve this with a tiny bit of extra overhead by doing
something like this:
def cant_sleep_clown_will_eat_me():
reactor.callLater(0, cant_sleep_clown_will_eat_me)
cant_sleep_clown_will_eat_me()
Will give this a go
Does this actually improve your latency?
-glyph
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