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Editor to share with you ext4 how to achieve delay stap script, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

#! / bin/sh

STAP_FILE_PATH= "/ tmp/moderate-ext4.stp"

MODERATE_EXT4_FUNCTIONS= (

# ext4 direct io function

"ext4_direct_IO"

# ext4 page related functions

# "ext4_readpages"

# "ext4_writepage"

# ext4 aio related functions

"generic_file_aio_read"

"ext4_file_write"

# ext4 sync function

"ext4_sync_file"

)

Function error ()

{

Echo $@

Exit 1

}

Function probe_functions ()

{

Local delay=$ {1VR-"1"}

Rm $STAP_FILE_PATH & > / dev/null

# header

Cat $STAP_FILE_PATH

#! / usr/bin/stap-DSTP_NO_OVERLOAD

# Delay reads by 250 ms

# stap-v-g nfsd_delay_op.stp nfsd_read 250

% {

# undef STP_OVERLOAD

# include

%}

Function udelay (ms:long)% {

/ * guru * /

Udelay (THIS- > ms)

%}

EOF

For func_name in ${MODERATE_EXT4_FUNCTIONS [@]}; do

If [[$func_name = ~ "ext4"]; then

# ext4 module probe body

Cat $STAP_FILE_PATH

Probe module ("ext4"). Function ("$func_name"). Return

{

Udelay ($delay)

}

EOF

Else

# kernel probe body

Cat $STAP_FILE_PATH

Probe kernel.function ("$func_name") .return

{

Udelay ($delay)

}

EOF

Fi

Done

}

Function usage ()

{

Local program= `basename $0`

Echo "Usage: $program is a tool to moderate ext4's io based on systemtap"

Echo "the only option is time, and the unit is milliseconds"

Exit 1

}

Function main () {

If ["$1" = "- h"] | | ["$1" = "--help"]; then

Usage

Fi

Which stap & > / dev/null | | yum-b current intall-y systemtap

Probe_functions $1

Stap-v-g $STAP_FILE_PATH

}

Main $1

The above is all the content of the article "how to implement the timed stap script in ext4". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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