The following are demonstrations of the hotuser DTrace program.

Here, hotuser is run on a test program called "dofuncs", which is hard coded

to spend half its time in delta(), a third in beta() and a sixth in alpha().

# ./hotuser -c ./dofuncs

Sampling... Hit Ctrl-C to end.

^C

FUNCTION COUNT PCNT

dofuncs`alpha 511 16.5%

dofuncs`beta 1029 33.3%

dofuncs`delta 1552 50.2%

hotuser has accurately sampled which user-level functions are on the CPU,

producing a report of the expected breakdown. The hottest user-level function

is delta(), which was sampled 1552 times - 50.2% of the total samples.

Now hotuser is run on gunzip, to find which functions are most often

on the CPU,

# ./hotuser -c 'gunzip contents.gz'

Sampling... Hit Ctrl-C to end.

FUNCTION COUNT PCNT

libc.so.1`_free_unlocked 1 0.1%

gunzip`unzip 1 0.1%

ld.so.1`strcmp 1 0.1%

gunzip`inflate_dynamic 1 0.1%

libc.so.1`_write 1 0.1%

gunzip`write_buf 1 0.1%

gunzip`0x2d990 2 0.3%

libc.so.1`write 2 0.3%

gunzip`0x2d994 2 0.3%

ld.so.1`rtld_db_preinit 3 0.4%

gunzip`0x2d98c 7 0.9%

gunzip`huft_build 9 1.2%

libc_psr.so.1`memcpy 138 18.5%

gunzip`inflate_codes 233 31.2%

gunzip`updcrc 344 46.1%

This shows that updcrc() was sampled 344 times, and 46.1% of the total

samples.

A -l option will provide a breakdown on libraries only. hotuser

is run on gzip to show library usage only,

# ./hotuser -lc 'gzip contents'

Sampling... Hit Ctrl-C to end.

LIBRARY COUNT PCNT

libc.so.1 2 0.0%

libc_psr.so.1 37 0.9%

gzip 4113 99.1%

This shows that code in the gzip binary itself was on the CPU 99.1% of

the sample times, with libc_psr.so.1 code on the CPU 0.9% of the time.

The following shows library usage of mozilla. The pgrep command is used to

match the most recent PID of mozilla-bin.

# ./hotuser -lp `pgrep -n mozilla-bin`

Sampling... Hit Ctrl-C to end.

^C

LIBRARY COUNT PCNT

libplds4.so 1 0.1%

libappcomps.so 1 0.1%

libi18n.so 1 0.1%

libuconv.so 1 0.1%

libpref.so 1 0.1%

libblueprint.so 1 0.1%

libz.so.1 2 0.2%

libcaps.so 2 0.2%

libXrender.so.1 2 0.2%

libimglib2.so 2 0.2%

libXft.so.2 3 0.3%

libCrun.so.1 3 0.3%

libdocshell.so 3 0.3%

libplc4.so 4 0.4%

libgtk-x11-2.0.so.0.400.9 5 0.5%

libjsd.so 5 0.5%

libX11.so.4 5 0.5%

libnecko.so 8 0.9%

libwidget_gtk2.so 9 1.0%

libgkgfx.so 13 1.4%

libglib-2.0.so.0.400.1 14 1.5%

libgfx_gtk.so 18 2.0%

libnspr4.so 20 2.2%

libxpconnect.so 22 2.4%

libgdk-x11-2.0.so.0.400.9 23 2.5%

libgobject-2.0.so.0.400.1 25 2.7%

libhtmlpars.so 27 3.0%

libfontconfig.so.1 41 4.5%

libxpcom.so 49 5.4%

mozilla-bin 55 6.0%

libmozjs.so 80 8.8%

libc.so.1 115 12.6%

libgklayout.so 352 38.6%

This shows that 352 samples found code from libgklayout.so running, which

was 38.6% of the samples.