Profile and improve CPU usage about appimaged HOT 8 OPEN

# xubuntu-16.04.1-desktop-amd64.iso

systemctl --user stop appimaged
sudo apt install -y oprofile
find $HOME -type f -name '*appimagekit*' -delete
sudo operf /usr/bin/appimaged -v
# Let it run until it quiesces (CPU usage drops)
opreport --symbols | head -n 20
(...)
samples  %        image name               app name                 symbol name
289921   12.6670  libc-2.23.so             appimaged                _int_malloc
288744   12.6156  libc-2.23.so             appimaged                _int_free
196628    8.5909  libc-2.23.so             appimaged                malloc
177278    7.7455  libc-2.23.so             appimaged                re_compile_internal
171381    7.4879  libc-2.23.so             appimaged                build_trtable
98853     4.3190  libc-2.23.so             appimaged                malloc_consolidate
82260     3.5940  libc-2.23.so             appimaged                free
66660     2.9125  libxml2.so.2.9.3         update-mime-database.real /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.3
59574     2.6029  libc-2.23.so             appimaged                realloc
51104     2.2328  libc-2.23.so             appimaged                re_acquire_state_context
47284     2.0659  appimaged                appimaged                lzma_decode
43237     1.8891  libc-2.23.so             appimaged                calc_eclosure_iter
43129     1.8844  libc-2.23.so             appimaged                free_dfa_content
33326     1.4561  libc-2.23.so             appimaged                re_node_set_merge.part.16
33097     1.4460  libz.so.1.2.8            appimaged                /lib/x86_64-linux-gnu/libz.so.1.2.8
31545     1.3782  libc-2.23.so             appimaged                re_dfa_add_node
30962     1.3528  libc-2.23.so             appimaged                re_search_internal

systemctl --user stop appimaged
sudo apt install -y oprofile
find $HOME -type f -name '*appimagekit*' -delete
sudo operf /usr/bin/appimaged -v
# Let it run until it quiesces (CPU usage drops)
opreport --symbols | head -n 20
(...)
samples  %        image name               app name                 symbol name
298166   12.8835  libc-2.23.so             appimaged                _int_malloc
290919   12.5703  libc-2.23.so             appimaged                _int_free
198783    8.5892  libc-2.23.so             appimaged                malloc
178815    7.7264  libc-2.23.so             appimaged                re_compile_internal
173222    7.4848  libc-2.23.so             appimaged                build_trtable
100736    4.3527  libc-2.23.so             appimaged                malloc_consolidate
81232     3.5100  libc-2.23.so             appimaged                free
68335     2.9527  libxml2.so.2.9.3         update-mime-database.real /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.3
60434     2.6113  libc-2.23.so             appimaged                realloc
51437     2.2225  libc-2.23.so             appimaged                re_acquire_state_context
47395     2.0479  appimaged                appimaged                lzma_decode
44080     1.9047  libc-2.23.so             appimaged                calc_eclosure_iter
43250     1.8688  libc-2.23.so             appimaged                free_dfa_content
33316     1.4396  libz.so.1.2.8            appimaged                /lib/x86_64-linux-gnu/libz.so.1.2.8
33233     1.4360  libc-2.23.so             appimaged                re_node_set_merge.part.16
32048     1.3848  libc-2.23.so             appimaged                re_dfa_add_node
31197     1.3480  libc-2.23.so             appimaged                re_search_internal

me@host ~ $ opreport --symbols | grep -e ' re_'

178815    7.7264  libc-2.23.so             appimaged                re_compile_internal
51437     2.2225  libc-2.23.so             appimaged                re_acquire_state_context
33233     1.4360  libc-2.23.so             appimaged                re_node_set_merge.part.16
32048     1.3848  libc-2.23.so             appimaged                re_dfa_add_node
31197     1.3480  libc-2.23.so             appimaged                re_search_internal
17208     0.7435  libc-2.23.so             appimaged                re_node_set_insert
13086     0.5654  libc-2.23.so             appimaged                re_compile_fastmap_iter.isra.26
11600     0.5012  libc-2.23.so             appimaged                re_string_reconstruct
4788      0.2069  libc-2.23.so             appimaged                re_string_context_at
4719      0.2039  libc-2.23.so             appimaged                re_acquire_state
3776      0.1632  libc-2.23.so             appimaged                re_node_set_add_intersect.part.18
1529      0.0661  libc-2.23.so             appimaged                re_node_set_contains.isra.3
920       0.0398  libc-2.23.so             appimaged                re_compile_fastmap

me@host ~ $ opreport --symbols | grep mime
(...)
68335     2.9527  libxml2.so.2.9.3         update-mime-database.real /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.3
29447     1.2724  update-mime-database.real update-mime-database.real /usr/bin/update-mime-database.real
19588     0.8464  libc-2.23.so             update-mime-database.real malloc_consolidate
12706     0.5490  libc-2.23.so             update-mime-database.real _int_malloc
8470      0.3660  libc-2.23.so             update-mime-database.real _int_free
6639      0.2869  libc-2.23.so             update-mime-database.real malloc
5649      0.2441  libc-2.23.so             update-mime-database.real __GI___strcmp_ssse3

samples  %        image name               app name                 symbol name
2809941  77.0336  libc-2.24.so             appimaged                /lib/x86_64-linux-gnu/libc-2.24.so
177760    4.8732  libxml2.so.2.9.4         update-mime-database.real /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.4
167353    4.5879  libc-2.24.so             update-mime-database.real /lib/x86_64-linux-gnu/libc-2.24.so
95246     2.6111  appimaged                appimaged                lzma_decode
90290     2.4753  update-mime-database.real update-mime-database.real /usr/bin/update-mime-database.real
44537     1.2210  libz.so.1.2.8            appimaged                /lib/x86_64-linux-gnu/libz.so.1.2.8

# xubuntu-18.04-desktop-amd64.iso

systemctl --user stop appimaged
sudo apt install -y oprofile
find $HOME -type f -name '*appimagekit*' -delete
sudo operf /usr/bin/appimaged -v
# Let it run until it quiesces (CPU usage drops)
opreport --symbols | head -n 20
(...)
samples  %        image name               app name                 symbol name
269956   12.7213  libc-2.27.so             operf                    free
249689   11.7662  libc-2.27.so             operf                    _int_malloc
200959    9.4699  libc-2.27.so             operf                    build_trtable
191166    9.0084  libc-2.27.so             operf                    re_compile_internal
110790    5.2208  libc-2.27.so             operf                    malloc
85642     4.0358  libc-2.27.so             operf                    malloc_consolidate
75837     3.5737  libxml2.so.2.9.4         update-mime-database     /usr/lib/x86_64-linux-gnu/libxml2.so.2.9.4
66128     3.1162  libc-2.27.so             operf                    realloc
54770     2.5810  libc-2.27.so             operf                    re_acquire_state_context
51748     2.4386  libc-2.27.so             operf                    free_dfa_content
48772     2.2983  libc-2.27.so             operf                    calc_eclosure_iter
48499     2.2854  appimaged                operf                    lzma_decode
34220     1.6126  libz.so.1.2.11           operf                    /lib/x86_64-linux-gnu/libz.so.1.2.11
31714     1.4945  libc-2.27.so             operf                    calloc
31197     1.4701  libc-2.27.so             operf                    re_search_internal
29388     1.3849  libc-2.27.so             operf                    re_dfa_add_node
28154     1.3267  update-mime-database     update-mime-database     /usr/bin/update-mime-database