Messages in this thread | | | From | Namhyung Kim <> | Subject | [PATCHSET 0/9] perf: Improve cgroup profiling (v1) | Date | Wed, 28 Aug 2019 16:31:21 +0900 |
| |
Hello,
This work is to improve cgroup profiling in perf. Currently it only supports profiling tasks in a specific cgroup and there's no way to identify which cgroup the current sample belongs to. So I added PERF_SAMPLE_CGROUP to add cgroup info into each sample. It's a 64-bit integer having inode number of the cgroup. And kernel also generates PERF_RECORD_CGROUP event for new groups to correlate the inode number and cgroup name (path in the cgroup filesystem). The inode number can be read from userspace easily so it can synthesize the CGROUP event for existing groups.
Note that this only works for "perf_event" cgroups (obviously) so if users are still using cgroup-v1 interface, they need to have same hierarchy for subsystem(s) want to profile with it.
The testing result looks something like this:
[root@qemu build]# ./perf record --all-cgroups ./cgtest [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.009 MB perf.data (150 samples) ]
[root@qemu build]# ./perf report -s cgroup,comm --stdio # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 150 of event 'cpu-clock:pppH' # Event count (approx.): 37500000 # # Overhead cgroup Command # ........ .......... ....... # 32.00% /sub/cgrp2 looper2 28.00% /sub/cgrp1 looper1 25.33% /sub looper0 4.00% / cgtest 4.00% /sub cgtest 3.33% /sub/cgrp2 cgtest 2.67% /sub/cgrp1 cgtest 0.67% / looper0
The test program (cgtest) follows.
Thanks, Namhyung
Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Adrian Hunter <adrian.hunter@intel.com>
-------8<-----------------------------------------8<---------------- #define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <sched.h> #include <errno.h> #include <sys/stat.h> #include <sys/wait.h> #include <sys/prctl.h> #include <sys/mount.h>
char cgbase[] = "/sys/fs/cgroup/perf_event";
void mkcgrp(char *name) { char buf[256];
snprintf(buf, sizeof(buf), "%s%s", cgbase, name); if (mkdir(buf, 0755) < 0) perror("mkdir"); }
void rmcgrp(char *name) { char buf[256];
snprintf(buf, sizeof(buf), "%s%s", cgbase, name); if (rmdir(buf) < 0) perror("rmdir"); }
void setcgrp(char *name) { char buf[256]; int fd;
snprintf(buf, sizeof(buf), "%s%s/tasks", cgbase, name);
fd = open(buf, O_WRONLY); if (fd > 0) { if (write(fd, "0\n", 2) != 2) perror("write"); close(fd); } }
void create_sub_cgroup(int idx) { char buf[128];
snprintf(buf, sizeof(buf), "/sub/cgrp%d", idx); mkcgrp(buf); }
void remove_sub_cgroup(int idx) { char buf[128];
snprintf(buf, sizeof(buf), "/sub/cgrp%d", idx); rmcgrp(buf); }
void set_sub_cgroup(int idx) { char buf[128];
snprintf(buf, sizeof(buf), "/sub/cgrp%d", idx); setcgrp(buf); }
void set_task_name(int idx) { char buf[16];
snprintf(buf, sizeof(buf), "looper%d", idx); prctl(PR_SET_NAME, buf, 0, 0, 0); }
void loop(unsigned max) { volatile unsigned int count = 1;
while (count++ != max) { asm volatile ("pause"); } }
void worker(int idx, unsigned cnt, int new_ns) { int oldns;
create_sub_cgroup(idx); set_sub_cgroup(idx);
if (new_ns) { if (unshare(CLONE_NEWCGROUP) < 0) perror("unshare");
#if 0 /* FIXME */ if (unshare(CLONE_NEWNS) < 0) perror("unshare");
if (mount("none", "/sys", NULL, MS_REMOUNT | MS_REC | MS_SLAVE, NULL) < 0) perror("mount --make-rslave");
sleep(1); if (umount("/sys/fs/cgroup/perf_event") < 0) perror("umount");
if (mount("cgroup", "/sys/fs/cgroup/perf_event", "cgroup", MS_NODEV | MS_NOEXEC | MS_NOSUID, "perf_event") < 0) perror("mount again"); #endif }
if (fork() == 0) { set_task_name(idx); loop(cnt); exit(0); } wait(NULL); }
int main(int argc, char *argv[]) { int i, nr = 2; int new_ns = 1; unsigned cnt = 1000000; int fd;
if (argc > 1) nr = atoi(argv[1]); if (argc > 2) cnt = atoi(argv[2]); if (argc > 3) new_ns = atoi(argv[3]);
mkcgrp("/sub"); setcgrp("/sub");
for (i = 0; i < nr; i++) { if (fork() == 0) { worker(i+1, cnt, new_ns); exit(0); } }
set_task_name(0); loop(cnt);
for (i = 0; i < nr; i++) wait(NULL);
for (i = 0; i < nr; i++) remove_sub_cgroup(i+1);
setcgrp("/"); rmcgrp("/sub");
return 0; } -------8<-----------------------------------------8<----------------
Namhyung Kim (9): perf/core: Add PERF_RECORD_CGROUP event perf/core: Add PERF_SAMPLE_CGROUP feature perf tools: Basic support for CGROUP event perf tools: Maintain cgroup hierarchy perf report: Add 'cgroup' sort key perf record: Support synthesizing cgroup events perf record: Add --all-cgroups option perf top: Add --all-cgroups option perf script: Add --show-cgroup-events option
include/linux/perf_event.h | 1 + include/uapi/linux/perf_event.h | 18 ++- kernel/events/core.c | 128 ++++++++++++++++++++++ tools/include/uapi/linux/perf_event.h | 17 ++- tools/perf/Documentation/perf-record.txt | 5 +- tools/perf/Documentation/perf-report.txt | 1 + tools/perf/Documentation/perf-script.txt | 3 + tools/perf/Documentation/perf-top.txt | 4 + tools/perf/builtin-diff.c | 1 + tools/perf/builtin-record.c | 10 ++ tools/perf/builtin-report.c | 1 + tools/perf/builtin-script.c | 41 +++++++ tools/perf/builtin-top.c | 9 ++ tools/perf/lib/include/perf/event.h | 7 ++ tools/perf/util/cgroup.c | 75 ++++++++++++- tools/perf/util/cgroup.h | 16 ++- tools/perf/util/event.c | 133 +++++++++++++++++++++++ tools/perf/util/event.h | 11 ++ tools/perf/util/evsel.c | 12 ++ tools/perf/util/hist.c | 7 ++ tools/perf/util/hist.h | 1 + tools/perf/util/machine.c | 19 ++++ tools/perf/util/machine.h | 3 + tools/perf/util/record.h | 1 + tools/perf/util/session.c | 8 ++ tools/perf/util/sort.c | 31 ++++++ tools/perf/util/sort.h | 2 + tools/perf/util/tool.h | 2 + 28 files changed, 556 insertions(+), 11 deletions(-)
-- 2.23.0.187.g17f5b7556c-goog
| |