The YBOS spy daemon

The main task of a spy daemon is to provide transparent access to events that are not present in a local circular buffer. Furthermore, the spy daemon must balance between high efficiency, obtained prefetching the events, and low system load, obtained minimising unneeded event prefetches.

The YBOS spy daemon reads the events from a YBOS file and packs them as if they came from the buffer between a farm builder and a farm recorder

Program syntax

ybosspydaemon [-n processname]

Commands

init [circbuf]: Initialize the process. Must be called at startup and after any error.
The circbuf parameter, if present, sets the lname shared variable.
Puts the process in the INIT_STATE.
start [filename]: Open the file and start serving. Can be used only when the process is in the INIT_STATE.
The filename parameter, if present, sets the fname shared variable.
If the filename is "-", no file is opened, but the process starts serving with no events. Moreover, the fname shared variable is not updated.
Puts the process in the RUNNING_STATE.
pause: Pause reading new events. Can be used only when the process is in the RUNNING_STATE.
Puts the process in the PAUSE_STATE.
resume: Resume reading new events (if in PAUSE_STATE).
Puts the process in the RUNNING_STATE.
reconnect [filename]: Close the old file and open another one. Can be used only when the process is in the RUNNING_STATE or PAUSE_STATE.
The filename parameter, if present, sets the fname shared variable.
disconnect: Close the file, but continue serving empty. Can be used only when the process is in the RUNNING_STATE or PAUSE_STATE.
update: Update shared variables. Can be used only when the process is in the RUNNING_STATE.
end: End serving. Can be used only when the process is in the RUNNING_STATE.
Puts the process in the INIT_STATE.
exit: End serving and kill the process.
Calls the end command before using exit.

Shared variables

Name	Type	Access	Description	Default value
runstate	INTEGER	R	Status of the process. Can be on of the following: UNDEFINED_STATE INIT_STATE RUNNING_STATE PAUSE_STATE	UNDEFINED_STATE
timeout_us	INTEGER	R/W	Timeout time in microseconds	10000
timeouts	INTEGER	R	Number of timeouts from the start of serving.	0 Reset after the start command.
fname	STRING	R/W	Name of the YBOS file.	a.ybos
lname	STRING	R/W	Name of the circular buffer.	/tmp/B_1_1
circsize	INTEGER	R/W	Size of the circular buffer.	1 Mb
bufsize	INTEGER	R/W	Size of the packing buffer.	256 kb
ignored	INTEGER	R	Number of events ignored because too large.	0 Reset after the start command.
maxevents	INTEGER	R/W	Maximum number of events per packet.	100
skip	INTEGER	R/W	Number of events to skip for every event read.	0
at_EOF	INTEGER	R	0 if the daemon is reading from a file, 1 else	1
upfreq	INTEGER	R/W	Long term status update frequency. (Expressed in number of loops) If ==0, updated at short term update only.	5
upfreq_l	INTEGER	R/W	Short term status update frequency. (Expressed in number of loops) It also updates long term status. If ==0, the automatic update is disabled.	10
sg_msecs	INTEGER	R	Miliseconds from the last start or resume.	0 Updated every upfreq cycles.
sg_packs	INTEGER	R	Number of packets received from the last start or resume.	0 Updated every upfreq cycles.
sg_cpu	INTEGER	R	CPU used from the last start or resume. (Expressed in 10^-9)	0 Updated every upfreq cycles.
sg_gbytes	INTEGER	R	GBytes received (2³⁰) from the last start or resume.	0 Updated every upfreq cycles.
sg_bytes	INTEGER	R	Bytes received (mod GB) from the last start or resume.	0 Updated every upfreq cycles.
sg_uptime	INTEGER	R	The time at the last long term status update. (As reported by time) Set to 0 if no update yet.	0 Updated every upfreq cycles.
sl_msecs	INTEGER	R	Miliseconds from the last update.	0 Updated every upfreq_l cycles.
sl_packs	INTEGER	R	Number of packets received from the last update.	0 Updated every upfreq_l cycles.
sl_cpu	INTEGER	R	CPU used from the last update. (Expressed in 10^-9)	0 Updated every upfreq_l cycles.
sl_bytes	INTEGER	R	Bytes received from the last update.	0 Updated every upfreq_l cycles.
sl_uptime	INTEGER	R	The time at the last short term status update. (As reported by time) Set to 0 if no update yet.	0 Updated every upfreq_l cycles.

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Send comments to: Igor Sfiligoi

Created	:	15.12.1998
Last modified	:	15.12.1998