Re: [PATCH v9] kallsyms: Add self-test facility

Luis Chamberlain
2022-11-15T08:42:56Z

On Tue, Nov 15, 2022 at 04:33:48PM +0800, Zhen Lei wrote:
> Added test cases for basic functions and performance of functions
> kallsyms_lookup_name(), kallsyms_on_each_symbol() and
> kallsyms_on_each_match_symbol(). It also calculates the compression rate
> of the kallsyms compression algorithm for the current symbol set.
>
> The basic functions test begins by testing a set of symbols whose address
> values are known. Then, traverse all symbol addresses and find the
> corresponding symbol name based on the address. It's impossible to
> determine whether these addresses are correct, but we can use the above
> three functions along with the addresses to test each other. Due to the
> traversal operation of kallsyms_on_each_symbol() is too slow, only 60
> symbols can be tested in one second, so let it test on average once
> every 128 symbols. The other two functions validate all symbols.
>
> If the basic functions test is passed, print only performance test
> results. If the test fails, print error information, but do not perform
> subsequent performance tests.
>
> Start self-test automatically after system startup if
> CONFIG_KALLSYMS_SELFTEST=y.
>
> Example of output content: (prefix 'kallsyms_selftest:' is omitted
> start
> ---------------------------------------------------------
> | nr_symbols | compressed size | original size | ratio(%) |
> |---------------------------------------------------------|
> | 107543 | 1357912 | 2407433 | 56.40 |
> ---------------------------------------------------------
> kallsyms_lookup_name() looked up 107543 symbols
> The time spent on each symbol is (ns): min=630, max=35295, avg=7353
> kallsyms_on_each_symbol() traverse all: 11782628 ns
> kallsyms_on_each_match_symbol() traverse all: 9261 ns
> finish
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

Thanks! Queued onto module-next.

Luis