Hi Daisuke, On Wed, Mar 23, 2022 at 08:09:49AM +0000, d.hatayama@xxxxxxxxxxx wrote: > verify_namelist() uses strings command and scans full part of vmlinux > file to find linux_banner string. However, vmlinux file is quite large > these days, reaching over 500MB. As a result, this degradates start-up > time of crash command 10 or more seconds. (Of course, this depends on > machines you use for investigation, but I guess typically we cannot > use such powerful machines to investigate crash dump...) > > To resolve this issue, let's use bfd library and read linux_banner > string in vmlinux file directly. > > A simple benchmark shows the following result: > > Without the fix: > > # cat ./commands.txt > quit > # time ./crash -i ./commands.txt \ > /usr/lib/debug/lib/modules/5.16.15-201.fc35.x86_64/vmlinux \ > /var/crash/*/vmcore >/dev/null 2>&1 > > real 0m20.251s > user 0m19.022s > sys 0m1.054s > > With the fix: > > # time ./crash -i ./commands.txt \ > /usr/lib/debug/lib/modules/5.16.15-201.fc35.x86_64/vmlinux \ > /var/crash/*/vmcore >/dev/null 2>&1 > > real 0m6.528s > user 0m6.143s > sys 0m0.431s > > Note that this commit keeps the original logic that uses strings > command for backward compatibility for in case. I tested this patch with my vmcore (over 10G). Before this patch: time ./crash -i ./commands.txt /root/t/vmlinux-5.4.119-1-gamematrix-015e /root/t/vmcore > /dev/null 2>&1 real 1m19.052s user 1m17.333s sys 0m1.675s After: #time ./crash -i ./commands.txt /root/t/vmlinux-5.4.119-1-gamematrix-015e /root/t/vmcore > /dev/null 2>&1 real 1m16.609s user 1m14.655s sys 0m1.903s It seems this patch does not improve too much. Thanks Huang Shijie -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki
