Request for systemtap scripts

[atoponce]

I understand that @behlendorf has written some systemtap scripts for troubleshooting ZFS. How can I get these?

[chrisrd]

@atoponce The scripts are specific to what you want to investigate. The first step might be to use para-callgraph.stp from the systemtap distribution. This shows you functions called, along with their arguments and return values. It takes two parameters: a set of functions to monitor, and a function at which to start/stop the monitoring, e.g. to monitor all the functions in all the module/zfs/*.c files, starting when the zpl_xattr_list function is called:

# stap /usr/share/doc/systemtap/examples/general/para-callgraph.stp \
   'module("zfs").function("*@module/zfs/*.c")' \
   'module("zfs").function("zpl_xattr_list")' -c "getfattr -d aaaa"

For some examples, see #503, #1461. A search of the ZoL issues for stap or systemtap may also be useful:

https://github.com/zfsonlinux/zfs/search?q=stap&type=Issues
https://github.com/zfsonlinux/zfs/search?q=systemtap&type=Issues

Note: I'm no expert, what I know of systemtap I've learnt here!

[behlendorf]

I think it would be great if there was a generic ZFS tapset for Systemtap. Alas all the scripts I've written in the past have been specific to troubleshooting an individual issue. Writing generic tools is considerably more involved although I'd love to see it happen.

Related to this we have been adding more kstats for increased visibility. You may find the following useful.

/proc/spl/kstat/zfs/rpool/io
/proc/spl/kstat/zfs/rpool/dmu_tx_assign
/proc/spl/kstat/zfs/rpool/txgs
/proc/spl/kstat/zfs/rpool/reads
/proc/spl/kstat/zfs/vdev_cache_stats
/proc/spl/kstat/zfs/zil
/proc/spl/kstat/zfs/arcstats
/proc/spl/kstat/zfs/dmu_tx
/proc/spl/kstat/zfs/zfetchstats
/proc/spl/kstat/zfs/dbufs
/proc/spl/kstat/zfs/xuio_stats
/proc/spl/kstat/zfs/fm

[atoponce]

I know that scripts are written for very specific troubleshooting cases. Just looking to see what's out there, I guess, and where I can go. I'm just learning systemtap myself, so if I can help to contribute generic scripts, I will. Thanks.

[rlaager]

This isn't directly related, but see also: https://github.com/iovisor/bcc