Re: [HELP] Systemtap fails to load kernel module

[Shuxin Yang <shuxinyang dot oss at gmail dot com>]

Hi,

   I used bulk-mode before to collect user-space call-graph of web 
servers using the
script 
https://github.com/openresty/nginx-systemtap-toolkit/blob/master/sample-bt

   stap generates bunch of files,  only one has data, which is 
consistent with our settings --
we set CPU affinity such that each web-server is bound to a particular CPU.

   The problem and the only problem is that the merged resulting file 
is suspicious
as the sample-count seems to be significantly less than the one we 
collected using
non-bulk mode.

  Do we need to raise the sampling frequency for bulk mode?

Thanks
Shuxin


On 01/07/2016 10:43 AM, Frank Ch. Eigler wrote:
> Hi -
>
> > [...]
> > ERROR: context (size 66144) allocation failed
> > WARNING: /usr/local/systemtap/bin/staprun exited with status: 1
> > [...]
> The context structure is allocated per-cpu, so for high-cpu-count
> boxes can be a problem.  You must be running stap v2.4 or older, based
> on that message.  With newer stap, the context sizes are sometimes
> dramatically smaller for the same script.
>
> - FChE