[Rd] Very slow plot rendering with X11 on CentOS 5.5

[Henrik Bengtsson]

For whatever it is worth, a long time ago I had this problem when "ssh
-X" connecting to a server and doing simple plots such as plot(1:10).
It was painfully slow and I could see how each data points was
plotted.  After using X11.options(type="Xlib") in R things was back to
normal (fast) again.  I think the default before was
X11.options(type="cairo").

My $0.02

/Henrik

On Tue, Sep 28, 2010 at 3:19 PM, R P Herrold <herrold at owlriver.com> wrote:
> On Tue, 28 Sep 2010, Weigand, Stephen D. wrote:
>
>> I am connecting from a PC to a Linux system running CentOS
>> release 5.5 (Final) and it is extremely slow to render plots
>> to the X11 device.
>
>> The Linux timings are just awful, particularly using
>> X-Win32. Cairo vs. Xlib doesn't seem to matter much.
>
> I have to think it is display rendering load at the displaying unit [an X
> server], or network latencies in getting the detail from the producer [an X
> client] to the displaying unit [an X server]
>
> With centos 5 on a local X display [so the X client, and the X server do not
> have to push the content through the X fowarding and across the network
> sockets, but rather can go through the lo interface under Linux]:
>
>> f <- function(n){
>
> +   for(i in 1:n) qqnorm(rnorm(100))
> + }
>>
>> system.time(f(20))
>
>   user  system elapsed
>  0.220   0.028   2.417
>>
>
> which is quite sprightly ;)
>
> -------------------
>
> Then when I run it on the same hardware, but through two SSH hops, to, and
> back from a remote unit in the local subnet, things fall apart:
>
> [herrold at centos-5 ~]$ ssh xps400
> Last login: Tue Sep 28 11:00:05 2010 from centos-5.first.lan
> [herrold at xps400 ~]$ ssh centos-5
> herrold at centos-5's password:
> Last login: Tue Sep 28 09:13:50 2010
> [herrold at centos-5 ~]$ R
>  ...
>>
>> f <- function(n){
>
> +   for(i in 1:n) qqnorm(rnorm(100))
> + }
>>
>> system.time(f(20))
>
>   user  system elapsed
>  0.352   0.272  29.681
>>
>
> -------------------
>
> I build my own R packaging under CentOS and do not have a packaging suitable
> for the architecture of that intermediate box -- installing R to a Debian
> testing box, and running the X forwarding connection only one hop, it is
> again visually rebdered MUCH slower.  I get:
>
>> system.time(f(20))
>
>   user  system elapsed
>  0.644   0.212  45.089
>>
>
> yikes  ;)
>
> I'll get a packaging built under CentOS 5 on that other architecture
> overnight, and supplement this post
>
> -- Russ herrold
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>