Em Wed, Aug 05, 2015 at 04:17:42PM +0200, Milian Wolff escreveu: > On Tuesday 04 August 2015 12:27:46 Arnaldo Carvalho de Melo wrote: > > [acme@zoo linux]$ trace usleep 1 > > Error: No permissions to read > > /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit) > > Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' > This message I do not get, not even with my perf compiled from the v4.2-rc5 > tag. And it is exactly what I was asking for. > <snip> > > I guess what fixes what you report is this cset:
> > commit ab85785aa13c36440a91a8e9f7616357de411a1f > > tools lib api debugfs: Check for tracefs when reporting errors > > [acme@zoo linux]$ git describe ab85785aa13c36440a91a8e9f7616357de411a1f > > v4.2-rc1-17-gab85785aa13c > > So, can you try running the perf tools, built from the latest 4.2-rc > > codebase to see if it behaves as you expect? > This is not included in 4.2-rc5 as far as I can see: > $ git describe > v4.2-rc5-2-ga64d3e5 > $ git show ab85785aa13c36440a91a8e9f7616357de411a1f > fatal: bad object ab85785aa13c36440a91a8e9f7616357de411a1f > $ git log --grep debugfs --oneline --author=Arnaldo > f816b3c tools lib fs debugfs: Check if debugfs is mounted when handling ENOENT > ... Oops, it is just in tip/perf/core, i.e. scheduled for 4.3 :-\ Wonder how difficult would be to cherry-pick that into perf/urgent. I.e. can you try doing something like: git cherry-pick ab85785aa13c36440a91a8e9f7616357de411a1f With a checked out v4.2-rc5, or better, torvalds/master, i.e. the top of Linus's git tree? It is possible that one or more patches just before this one, also in perf/core, may be needed. If it is easy, perhaps we can push it for 4.2 final. Ah, you may want to take a look at: https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/log/?h=perf/core To get from this: [root@zoo ~]# trace -e newfstatat,unlinkat rm /tmp/foo 0.489 ( 0.011 ms): rm/8428 newfstatat(dfd: CWD, filename: 0x9153f8, statbuf: 0x915368, flag: 256 ) = 0 0.508 ( 0.010 ms): rm/8428 unlinkat(dfd: CWD, pathname: 0x9140c0) = 0 [root@zoo ~]# After doing this: [root@zoo ~]# perf probe 'vfs_getname=getname_flags:72 pathname=filename:string' Added new event: probe:vfs_getname (on getname_flags:72 with pathname=filename:string) You can now use it in all perf tools, such as: perf record -e probe:vfs_getname -aR sleep 1 To this: [root@zoo ~]# trace -e newfstatat,unlinkat rm /tmp/foo rm: cannot remove ‘/tmp/foo’: No such file or directory 0.503 ( 0.007 ms): rm/8480 newfstatat(dfd: CWD, filename: /tmp/foo, statbuf: 0x2370368, flag: 256) = -1 ENOENT No such file or directory 0.514 ( 0.004 ms): rm/8480 unlinkat(dfd: CWD, pathname: /tmp/foo) = -1 ENOENT No such file or directory [root@zoo ~]# Auto inserting that probe remains to be done, but for now can be done just once per boot. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
