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This patch introduces a cgroup identifier entry field in perf report to identify or distinguish data of different cgroups. It uses the device number and inode number of cgroup namespace, included in perf data with the new PERF_RECORD_NAMESPACES event, as cgroup identifier. With the assumption that each container is created with it's own cgroup namespace, this allows assessment/analysis of multiple containers at once. A simple test for this would be to clone a few processes passing SIGCHILD & CLONE_NEWCROUP flags to each of them, execute shell and run different workloads on each of those contexts, while running perf record command with --namespaces option. Shown below is the output of perf report, sorted with cgroup identifier, on perf.data generated with the above test scenario, clearly indicating one context's considerable use of kernel memory in comparison with others: $ perf report -s cgroup_id,sample --stdio # # Total Lost Samples: 0 # # Samples: 5K of event 'kmem:kmalloc' # Event count (approx.): 5965 # # Overhead cgroup id (dev/inode) Samples # ........ ..................... ............ # 81.27% 3/0xeffffffb 4848 16.24% 3/0xf00000d0 969 1.16% 3/0xf00000ce 69 0.82% 3/0xf00000cf 49 0.50% 0/0x0 30 While this is a start, there is further scope of improving this. For example, instead of cgroup namespace's device and inode numbers, dev and inode numbers of some or all namespaces may be used to distinguish which processes are running in a given container context. Also, scripts to map device and inode info to containers sounds plausible for better tracing of containers. Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Aravinda Prasad <aravinda@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sargun Dhillon <sargun@sargun.me> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/148891933338.25309.756882900782042645.stgit@hbathini.in.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.