On Tue, Sep 28, 2021 at 12:03:04PM +0200, Mauro Carvalho Chehab wrote: > Em Mon, 27 Sep 2021 17:48:05 +0200 > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu: > > > On Mon, Sep 27, 2021 at 03:39:42PM +0200, Mauro Carvalho Chehab wrote: > > > Em Mon, 27 Sep 2021 11:23:20 +0200 > > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu: > > > > > > > On Mon, Sep 27, 2021 at 10:55:53AM +0200, Mauro Carvalho Chehab wrote: > > > > > Em Thu, 23 Sep 2021 19:13:04 +0200 > > > > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu: > > > > > > > > > > > On Thu, Sep 23, 2021 at 05:41:11PM +0200, Mauro Carvalho Chehab wrote: > > > > > > > Hi Greg, > > > > > > > > > > > > > > As requested, this is exactly the same changes, rebased on the top of > > > > > > > driver-core/driver-core-next. > > > > > > > > > > > > > > - > > > > > > > > > > > > > > It follows a series of improvements for get_abi.pl. it is on the top of driver-core/driver-core-next. > > > > > > > > > > > > > > With such changes, on my development tree, the script is taking 6 seconds to run > > > > > > > on my desktop: > > > > > > > > > > > > > > $ !1076 > > > > > > > $ time ./scripts/get_abi.pl undefined |sort >undefined_after && cat undefined_after| perl -ne 'print "$1\n" if (m#.*/(\S+) not found#)'|sort|uniq -c|sort -nr >undefined_symbols; wc -l undefined_after undefined_symbols > > > > > > > > > > > > > > real 0m6,292s > > > > > > > user 0m5,640s > > > > > > > sys 0m0,634s > > > > > > > 6838 undefined_after > > > > > > > 808 undefined_symbols > > > > > > > 7646 total > > > > > > > > > > > > > > And 7 seconds on a Dell Precision 5820: > > > > > > > > > > > > > > $ 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 0m7.162s > > > > > > > user 0m5.836s > > > > > > > sys 0m1.329s > > > > > > > 6548 undefined > > > > > > > 772 undefined_symbols > > > > > > > > > > > > > > Both tests were done against this tree (based on today's linux-next): > > > > > > > > > > > > > > $ https://git.kernel.org/pub/scm/linux/kernel/git/mchehab/devel.git/log/?h=get_abi_undefined-latest > > > > > > > > > > > > > > It should be noticed that, as my tree has several ABI fixes, the time to run the > > > > > > > script is likely less than if you run on your tree, as there will be less symbols to > > > > > > > be reported, and the algorithm is optimized to reduce the number of regexes > > > > > > > when a symbol is found. > > > > > > > > > > > > > > Besides optimizing and improving the seek logic, this series also change the > > > > > > > debug logic. It how receives a bitmap, where "8" means to print the regexes > > > > > > > that will be used by "undefined" command: > > > > > > > > > > > > > > $ time ./scripts/get_abi.pl undefined --debug 8 >foo > > > > > > > real 0m17,189s > > > > > > > user 0m13,940s > > > > > > > sys 0m2,404s > > > > > > > > > > > > > > $wc -l foo > > > > > > > 18421939 foo > > > > > > > > > > > > > > $ cat foo > > > > > > > ... > > > > > > > /sys/kernel/kexec_crash_loaded =~ /^(?^:^/sys/.*/iio\:device.*/in_voltage.*_scale_available$)$/ > > > > > > > /sys/kernel/kexec_crash_loaded =~ /^(?^:^/sys/.*/iio\:device.*/out_voltage.*_scale_available$)$/ > > > > > > > /sys/kernel/kexec_crash_loaded =~ /^(?^:^/sys/.*/iio\:device.*/out_altvoltage.*_scale_available$)$/ > > > > > > > /sys/kernel/kexec_crash_loaded =~ /^(?^:^/sys/.*/iio\:device.*/in_pressure.*_scale_available$)$/ > > > > > > > ... > > > > > > > > > > > > > > On other words, on my desktop, the /sys match is performing >18M regular > > > > > > > expression searches, which takes 6,2 seconds (or 17,2 seconds, if debug is > > > > > > > enabled and sent to an area on my nvme storage). > > > > > > > > > > > > Better, it's down to 10 minutes on my machine now: > > > > > > > > > > > > real 10m39.218s > > > > > > user 10m37.742s > > > > > > sys 0m0.775s > > > > > > > > > > A lot better, but not clear why it is still taking ~40x more than here... > > > > > It could well be due to the other ABI changes yet to be applied > > > > > (I'll submit it probably later today), but it could also be related to > > > > > something else. Could this be due to disk writes? > > > > > > > > Disk writes to where for what? This is a very fast disk (nvme raid > > > > array) It's also a very "big" system, with lots of sysfs files: > > > > > > > > $ find /sys/devices/ -type f | wc -l > > > > 44334 > > > > > > Ok. Maybe that partially explains why it is taking so long, as the > > > number of regex to compare will increase (not linearly). > > > > No idea. I just ran it on my laptop and it took only 5 seconds. > > Ok, 5 seconds is similar to what I got here on the machines I > tested so far. I'm waiting for a (shared) big machine to be available > in order to be able to do some tests on it. > > > Hm, you aren't reading the values of the sysfs files, right? > > No. Just retrieving the directory contents. That part is actually > fast: it takes less than 2 seconds here to read all ABI + traverse > sysfs directories. Also, from your past logs, the time is spent > later on, when it is handling the regex. On that time, there are > just the regex parsing and printing the results. > > > Anything I can do to run to help figure out where the script is taking > > so long? > > Not sure if it is worth the efforts. I mean, the relationship > between the number of processed sysfs nodes and the number of regex > to be tested (using big-oh and big-omega notation) should be between > Ω(n . log(n)) and O(n^2 . log(n)). There's not much space left for > optimizing it, I guess. > > So, I would expect that a big server would take a log more time to > process, it, due to the larger number of sysfs entries. > > Also, if one wants to speedup on a big machine, it could either > exclude some pattern, like: > > # Won't parse any PCI devices > $time ./scripts/get_abi.pl undefined --search-string '^(?!.*pci)' |wc -l > 8438 > > real 0m3,494s > user 0m2,829s > sys 0m0,658s That only takes 8 seconds on this box: $ time ./scripts/get_abi.pl undefined --search-string '^(?!.*pci)' |wc -l 18872 real 0m8.026s user 0m7.300s sys 0m0.726s > or (more likely) just search for an specific part of the ABI: > > # Seek ABI only for PCI devices > $ ./scripts/get_abi.pl undefined --search-string pci This takes much longer, I didn't want to wait the 10 minutes :) > --- > > After sleeping on it, I opted to implement some progress information. > > That will help to identify any issues that might be causing the > script to take so long to finish. > > I'll send the patches on a new series. Thanks, I'll go try those now... greg k-h
