Re: [Crash-utility] [PATCH v6 0/7] Improve kernel modules symbol searching performance

Hi Lijiang, On Sat, Oct 23, 2021 at 9:27 AM lijiang <lijiang(a)redhat.com&gt; wrote: > > On Sat, Oct 16, 2021 at 1:21 PM Tao Liu <ltao(a)redhat.com&gt; wrote: > > > > Currently the sequence for symbol_search to search a symbol is: 1) kernel > > symname hash table, 2) iterate all kernel symbols, 3) iterate all kernel > > modules and their symbols. In the worst case, if a non-exist symbol been > > searched, all 3 stages will be went through. The time consuming status for > > each stage is like: > > > > stage 1 stage 2 stage 3 > > 0.007000(ms) 0.593000(ms) 2.421000(ms) > > > > stage 3 takes too much time when comparing to stage 1. This patch introduces > > a symname hash table for kernel modules, to improve the performance of symbol > > searching. > > > > Functions symbol_search and symbol_exists are fundamental and widely used by > > other crash functions, thus the benefit of performance improvement can > > get accumulated. For example, "ps -m" and "irq" commands, which call > > the functions many times, will become faster with the patch. > > > > v5 -> v6: > > > > 1) Add mod_symname_hash table dump to help -s > > 2) Modified mod_symname_hash install/remove based on Kazu's suggestion. > > > > Tao Liu (7): > > Implement install and remove operations for mod_symname_hash > > Integrate symbol_search with mod_symname_hash search > > Extend symname_hash_search with hash table select > > Intergrate symbol_exists with mod_symname_hash search > > Sync module symbols into mod_symtable whenever module symbols change > > Refactor SYMNAME_HASH_INDEX macro to be a function > > Add mod_symname_hash table dump to help -s > > > > defs.h | 3 +- > > kernel.c | 1 + > > symbols.c | 261 +++++++++++++++++++++++++++++++++--------------------- > > 3 files changed, 164 insertions(+), 101 deletions(-) > > > > For the V6: Acked-by: Lianbo Jiang <lijiang(a)redhat.com&gt; > Thanks.