On Tue, Sep 21, 2021 at 08:16:33PM +0200, Mauro Carvalho Chehab wrote: > Em Tue, 21 Sep 2021 18:52:42 +0200 > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu: > > > On Sat, Sep 18, 2021 at 11:52:10AM +0200, Mauro Carvalho Chehab wrote: > > > Hi Greg, > > > > > > Add a new feature at get_abi.pl to optionally check for existing symbols > > > under /sys that won't match a "What:" inside Documentation/ABI. > > > > > > Such feature is very useful to detect missing documentation for ABI. > > > > > > This series brings a major speedup, plus it fixes a few border cases when > > > matching regexes that end with a ".*" or \d+. > > > > > > patch 1 changes get_abi.pl logic to handle multiple What: lines, in > > > order to make the script more robust; > > > > > > patch 2 adds the basic logic. It runs really quicky (up to 2 > > > seconds), but it doesn't use sysfs softlinks. > > > > > > Patch 3 adds support for parsing softlinks. It makes the script a > > > lot slower, making it take a couple of minutes to process the entire > > > sysfs files. It could be optimized in the future by using a graph, > > > but, for now, let's keep it simple. > > > > > > Patch 4 adds an optional parameter to allow filtering the results > > > using a regex given by the user. When this parameter is used > > > (which should be the normal usecase), it will only try to find softlinks > > > if the sysfs node matches a regex. > > > > > > Patch 5 improves the report by avoiding it to ignore What: that > > > ends with a wildcard. > > > > > > Patch 6 is a minor speedup. On a Dell Precision 5820, after patch 6, > > > results are: > > > > > > $ time ./scripts/get_abi.pl undefined |sort >undefined && cat undefined| perl -ne 'print "$1\n" if (m#.*/(\S+) not found#)'|sort|uniq -c|sort -nr >undefined_symbols; wc -l undefined; wc -l undefined_symbols > > > > > > real 2m35.563s > > > user 2m34.346s > > > sys 0m1.220s > > > 7595 undefined > > > 896 undefined_symbols > > > > > > Patch 7 makes a *huge* speedup: it basically switches a linear O(n^3) > > > search for links by a logic which handle symlinks using BFS. It > > > also addresses a border case that was making 'msi-irqs/\d+' regex to > > > be misparsed. > > > > > > After patch 7, it is 11 times faster: > > > > > > $ time ./scripts/get_abi.pl undefined |sort >undefined && cat undefined| perl -ne 'print "$1\n" if (m#.*/(\S+) not found#)'|sort|uniq -c|sort -nr >undefined_symbols; wc -l undefined; wc -l undefined_symbols > > > > > > real 0m14.137s > > > user 0m12.795s > > > sys 0m1.348s > > > 7030 undefined > > > 794 undefined_symbols > > > > > > (the difference on the number of undefined symbols are due to the fix for > > > it to properly handle 'msi-irqs/\d+' regex) > > > > > > - > > > > > > While this series is independent from Documentation/ABI changes, it > > > works best when applied from this tree, which also contain ABI fixes > > > and a couple of additions of frequent missed symbols on my machine: > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/mchehab/devel.git/log/?h=get_undefined_abi_v3 > > > > I've taken all of these, but get_abi.pl seems to be stuck in an endless > > loop or something. I gave up and stopped it after 14 minutes. It had > > stopped printing out anything after finding all of the pci attributes > > that are not documented :) > > It is probably not an endless loop, just there are too many vars to > check on your system, which could make it really slow. Ah, yes, I ran it overnight and got the following: $ time ./scripts/get_abi.pl undefined |sort >undefined && cat undefined| perl -ne 'print "$1\n" if (m#.*/(\S+) not found#)'|sort|uniq -c|sort -nr >undefined_symbols; wc -l undefined; wc -l undefined_symbols real 29m39.503s user 29m37.556s sys 0m0.851s 26669 undefined 765 undefined_symbols > The way the search algorithm works is that reduces the number of regex > expressions that will be checked for a given file entry at sysfs. It > does that by looking at the devnode name. For instance, when it checks for > this file: > > /sys/bus/pci/drivers/iosf_mbi_pci/bind > > The logic will seek only the "What:" expressions that end with "bind". > Currently, there are just two What expressions for it[1]: > > What: /sys/bus/fsl\-mc/drivers/.*/bind > What: /sys/bus/pci/drivers/.*/bind > > It will then run an O(n²) algorithm to seek: > > foreach my $a (@names) { > foreach my $w (split /\xac/, $what) { > if ($a =~ m#^$w$#) { > exact = 1; > last; > } > } > } > > Which runs quickly, when there are few regexs to seek. There are, > however, some What: expressions that end with a wildcard. Those are > harder to process. Right now, they're all grouped together, which > makes them slower. Most of the processing time are spent on those. > > I'm working right now on some strategy to also speed up the search > for them. Once I get something better, I'll send a patch series. > > -- > > [1] On a side note, there are currently some problems with the What: > definitions for bind/unbind, as: > > - it doesn't match all PCI devices; > - it doesn't match ACPI and other buses that also export > bind/unbind. > > > > > Anything I can do to help debug this? > > > > There are two parameters that can help to identify the issue: > > a) You can add a "--show-hints" parameter. This turns on some > prints that may help to identify what the script is doing. > It is not really a debug option, but it helps to identify > when some regexes are failing. > > b) You can limit the What expressions that will be parsed with: > --search-string <something> > > You can combine both. For instance, if you want to make it > a lot more verbose, you could run it as: > > ./scripts/get_abi.pl undefined --search-string /sys --show-hints Let me run this and time stamp it to see where it is getting hung up on. Give it another 30 minutes :) thanks, greg k-hj
