On Mon, 18 Oct 2021 21:26:16 +0800 Li Zhijian <lizhijian@xxxxxxxxxxxxxx> wrote: > LKP/0day observed that kselftests/ftrace cannot finish within 1 hour on > a 96 cpus platform where it hangs in the line like: > 'cat trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l' > subsystem-enable.tc > > It seems that trace will keep growing during it's read by 'cat' command. > Consequently, trace becomes too large to finish reading. > > replace 'cat trace' by: > $ sed -i 's/cat trace |/read_cached_trace |/g' $(find test.d -name "*.tc") > Instead, what happens if you add this command to each test? if [ -t options/pause-on-trace ]; then echo 1 > options/pause-on-trace fi We also need to add to the "initialize_ftrace" function in test.d/functions. if [ -t options/pause-on-trace ]; then echo 0 > options/pause-on-trace fi -- Steve > CC: Philip Li <philip.li@xxxxxxxxx> > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxxxxx> > ---