Here are the results of `strace -c` and the runtime with `-maxdepth 1` for `find`.
$ time find -maxdepth 1 -name '*.tsv' > /dev/null real 0m21.118s user 0m0.446s sys 0m0.577s $ time find -name '*.tsv' > /dev/null real 0m21.277s user 0m0.454s sys 0m0.636s $ time ./main.sh > /dev/null real 0m2.695s user 0m0.046s sys 0m0.057s $ cat main.sh #!/usr/bin/env bash # vim: set noexpandtab tabstop=2: echo *.tsv $ strace -c find -maxdepth 1 -name '*.tsv' > /dev/null % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 93.87 0.433259 18 23439 newfstatat 5.70 0.026288 25 1067 getdents 0.16 0.000725 45 16 10 open 0.06 0.000259 22 12 mmap 0.04 0.000190 32 6 read 0.03 0.000143 3 54 brk 0.03 0.000132 22 6 mprotect 0.03 0.000125 18 7 fstat 0.02 0.000109 109 1 1 access 0.02 0.000075 7 11 close 0.01 0.000064 21 3 3 stat 0.01 0.000036 4 10 fcntl 0.01 0.000035 35 1 execve 0.01 0.000033 33 1 munmap 0.00 0.000019 6 3 2 ioctl 0.00 0.000017 1 21 write 0.00 0.000017 17 1 arch_prctl 0.00 0.000016 16 1 uname 0.00 0.000014 7 2 fstatfs 0.00 0.000000 0 1 fchdir 0.00 0.000000 0 1 sysinfo 0.00 0.000000 0 1 openat ------ ----------- ----------- --------- --------- ---------------- 100.00 0.461556 24665 16 total $ strace -c ./main.sh > /dev/null % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 77.26 0.009637 9 1067 getdents 7.50 0.000936 49 19 8 open 3.99 0.000498 26 19 17 execve 2.38 0.000297 3 94 brk 2.18 0.000272 13 21 mmap 1.48 0.000185 4 46 23 stat 1.15 0.000144 12 12 mprotect 1.05 0.000131 15 9 read 0.99 0.000123 15 8 4 access 0.62 0.000077 8 10 fstat 0.51 0.000064 6 11 close 0.24 0.000030 30 1 munmap 0.24 0.000030 2 14 rt_sigaction 0.14 0.000017 9 2 arch_prctl 0.07 0.000009 2 6 rt_sigprocmask 0.06 0.000008 8 1 sysinfo 0.02 0.000003 1 4 4 ioctl 0.02 0.000002 0 70 write 0.02 0.000002 2 1 uname 0.02 0.000002 0 5 getuid 0.02 0.000002 0 5 getgid 0.02 0.000002 0 5 geteuid 0.02 0.000002 0 5 getegid 0.00 0.000000 0 3 lseek 0.00 0.000000 0 1 dup2 0.00 0.000000 0 1 getpid 0.00 0.000000 0 3 1 fcntl 0.00 0.000000 0 2 getrlimit 0.00 0.000000 0 1 getppid 0.00 0.000000 0 1 getpgrp ------ ----------- ----------- --------- --------- ---------------- 100.00 0.012473 1447 57 total On Wed, Jan 24, 2018 at 1:39 AM, Bernhard Voelker <m...@bernhard-voelker.de> wrote: > On 01/24/2018 01:44 AM, Peng Yu wrote: >> >> The attached files are the strace results for `echo` and `find`. Can >> anybody check if there is a way to improve the performance of `find` >> so that it can work as efficient as `echo` in this test case? Thanks. >> >> $ cat main.sh >> #!/usr/bin/env bash >> # vim: set noexpandtab tabstop=2: >> >> echo *.txt >> $ strace ./main.sh 2>/tmp/echo_strace.txt >> $ strace find -name '*.txt' > /dev/null 2>/tmp/find_strace.txt > > > First of all, please refrain from attaching such huge files when > sending to mailing lists like this; either upload them to a web > paste bin, or at least compress the files, e.g. the larger file > could have wasted only <100k instead of 2.3M. Thanks. > > Regarding the strace outputs: you did neither of the tips of > James (use "strace -c ...") nor of Dale (use "find -maxdepth 1 ..."), > so just from the number of system calls one could already guess > that the time is spent by the newfstatat() calls. > > We don't see what the previous getdents() calls return (strace -v), > but it seems that it doesn't include D_TYPE information on glusterfs. > Therefore, as you omitted the '-maxdepth 1' argument, find needs > to dig deeper to check if any of the entries have been a directory > (it would need to recurse to). > > BTW: you already got the same answer on your cross-posting [1]. > https://lists.gnu.org/r/coreutils/2018-01/msg00058.html > > Have a nice day, > Berny > > > -- Regards, Peng
