DocControl

Controlling SLASH2 Daemon Instances

Overview

The code for the control interface, named ctlapi, is in PFL. The interface for servers is implemented in pfl/ctlsvr.c. The interface for clients is implemented in pfl/ctlcli.c.

Features

globals

• options: inhuman, nodns, noheader
• colored output

show param

Client Interface

During command line parsing (e.g. msctl -s opstat:*aggr*), a queue of control messages are built up. Each time a new control request message is allocated, the last message that was created is sent. The new message is returned and message-specific settings may be set. Once parsing has completed, the final request message is sent and the response listening thread waits until end-of-file is received from the server.

Pack show requests:

• faults
• hash tables
• opstats
• journal
• listcaches
• LNET interfaces
• thread pflog levels
• progress meters
• mlists
• on-disk tables
• pools
• RPC services
• threads

Parse

Handling Received Messages

Most message types have two routines defined to handle and display messages sent from the server:

• Print header routine
• Print data routine

For example, psc_ctlmsg_hashtable_prhdr() and psc_ctlmsg_hashtable_prdat().

These routines need not display anything and may instead do some type of processing e.g. psc_ctlmsg_subsys_check which stores pflog subsystems later used by the pflog level display routines.

Server Interface

Some global data structure instances get automatically registered for statistics exportation and manipulation through daemon control sockets. For example, the SLASH2 fcmhdirty list cache is accessible like this:

$ msctl -L fcmhdirty

And the code just looks like this:

#include "pfl/listcache.h"

struct fidc_membh {
	...
	struct psc_listentry	fcmh_lentry;
};

struct psc_listcache fcmh_dirty_listcache;

lc_reginit(&fcmh_dirty_listcache, struct fidc_membh, fcmh_lentry,
    "fcmhdirty");