On Thu, 28 Jul 2016 02:57:38 +0530 Hari Bathini <[email protected]> wrote:
> If a uprobe event is set on a library function, and if a similar uprobe > event trace is needed for a container, a duplicate is created leaving > the uprobe list with multiple entries of the same function: > > $ perf probe --list > probe_libc:malloc (on 0x80490 in /lib64/libc.so.6) > probe_libc:malloc_1 (on __libc_malloc in /lib64/libc.so.6) > $ > > This can soon get out of hand if multiple containers want to probe the > same function/address in their libraries. This patch tries to resolve this > by adding uprobe event trace files to every new instance. Currently, perf > tool can leverage this by using --debugfs-dir option - something like > (assuming instance dir name is 'tracing'): > > $ perf --debugfs-dir=$MOUNT_PNT/instances probe /lib64/libc.so.6 malloc > $ > $ > $ perf --debugfs-dir=$MOUNT_PNT/instances probe --list > probe_libc:malloc (on __libc_malloc in /lib64/libc.so.6) > $ > > New uprobe events can be added to the uprobe_events file under the instance > directory and the profile information for these events will be available in > uprobe_profile file in the same instance directory. Hmm, this does change the behavior of normal instances. # cd /sys/kernel/debug/tracing # echo 'p /bin/bash:0x41adf0' > uprobe_events # ls events/uprobes enable filter p_bash_0x41adf0 # mkdir instances/foo # ls instances/foo/events/uprobes ls: cannot access instances/foo/events/uprobes: No such file or directory Usually, instances will have the same events as the top level directory. This will make uprobes, and only uprobes different. I'm not sure if this is a bad thing or not, I'll have to think about it more. But what would it take to have this only differ for containers, and not normal instances? -- Steve
