Messages in this thread Patch in this message |  | | From | David Carrillo-Cisneros <> | Subject | [PATCH v3 37/46] perf/x86/intel/cmt: add cont_monitoring to perf cgroup | Date | Sat, 29 Oct 2016 17:38:34 -0700 |
| |
Expose the attribute intel_cmt.cont_monitoring to perf cgroups using the newly introduced hook PERF_CGROUP_ARCH_CGRP_SUBSYS_ATTS.
The format of new attribute is a semi-colon separated list of per-package hexadecimal flags with missing an empty string assigned to zero.
echo "1;2" > g1/intel_cmt.cont_monitoring
Implies 0x1 for pkg 0 and 0x2 for pkg 1, 0x0 for all other pkgs.
This patch introduces the basic ideas of per-package uflags through a cgroup attribute. The format can be changed to match Intel CAT's schemata's file format once that is settled.
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> --- arch/x86/events/intel/cmt.c | 173 ++++++++++++++++++++++++++++++++++++++ arch/x86/include/asm/perf_event.h | 10 +++ 2 files changed, 183 insertions(+)
diff --git a/arch/x86/events/intel/cmt.c b/arch/x86/events/intel/cmt.c index 194038b..3ade923 100644 --- a/arch/x86/events/intel/cmt.c +++ b/arch/x86/events/intel/cmt.c @@ -2323,4 +2323,177 @@ inline void __intel_cmt_no_event_sched_in(void) #endif } +#ifdef CONFIG_CGROUP_PERF + +static int cmt_monitoring_seq_show(struct seq_file *m, void *v) +{ + struct perf_cgroup *cgrp = perf_cgroup_from_css(seq_css(m)); + struct monr *monr = NULL; + int p, nr_pkgs = topology_max_packages(); + + mutex_lock(&cmt_mutex); + + if (perf_cgroup_mon_started(cgrp)) + monr = monr_from_perf_cgroup(cgrp); + + for (p = 0; p < nr_pkgs; p++) { + seq_printf(m, "%x", monr ? monr->pkg_uflags[p] : 0); + if (p + 1 < nr_pkgs) + seq_puts(m, ";"); + } + + seq_puts(m, "\n"); + + mutex_unlock(&cmt_mutex); + return 0; +} + +/** + * Parses uflags string of the form: m1;m2;...;mP where m* are hexadecimal + * masks and P is less or equal than topology_max_packages(). Values not + * provided in the mask are assumed to be zero. + * On success, it allocates and returns an array. + */ +static enum cmt_user_flags *parse_pkg_uflags(char *buf, size_t nbytes) +{ + enum cmt_user_flags *uflags; + char *local_buf, *b, *m; + int err = 0, pmask, nr_pkgs = topology_max_packages(); + u16 p = 0; + + uflags = kcalloc(nr_pkgs, sizeof(*uflags), GFP_KERNEL); + if (!uflags) + return ERR_PTR(-ENOMEM); + + local_buf = kcalloc(nbytes, sizeof(char), GFP_KERNEL); + if (!local_buf) { + err = -ENOMEM; + goto error; + } + memcpy(local_buf, buf, nbytes); + b = local_buf; + while ((m = strsep(&b, ";")) != NULL) { + if (p >= nr_pkgs) { + err = -EINVAL; + goto error; + } + if (!*m) { + uflags[p] = 0; + continue; + } + err = kstrtoint(m, 16, &pmask); + if (err) + goto error; + uflags[p] = pmask; + if (uflags[p] > CMT_UF_MAX) { + err = -EINVAL; + goto error; + } + /* + * Non-zero flags must have CMT_UF_HAS_USER set. Otherwise + * there could be that monrs are not used. + */ + if (uflags[p] && (!(uflags[p] & CMT_UF_HAS_USER))) { + err = -EINVAL; + goto error; + } + p++; + } + + kfree(local_buf); + + return uflags; + +error: + kfree(local_buf); + kfree(uflags); + + return ERR_PTR(err); +} + +static ssize_t cmt_monitoring_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup_subsys_state *css = of_css(of); + struct monr *monr; + int err = 0; + bool is_mon; + enum cmt_user_flags *uflags; + + /* root is read-only */ + if (css == get_root_perf_css()) + return -EINVAL; + + buf = strstrip(buf); + + mutex_lock(&cmt_mutex); + monr_hrchy_acquire_mutexes(); + + /* Monitoring active, use new flags. */ + uflags = parse_pkg_uflags(buf, nbytes); + if (IS_ERR(uflags)) { + err = PTR_ERR(uflags); + goto exit_unlock; + } + + is_mon = perf_cgroup_mon_started(perf_cgroup_from_css(css)); + if (!is_mon) { + if (pkg_uflags_has_user(uflags)) { + err = __css_start_monitoring(css); + if (err) + goto exit_free; + } else { + /* + * uflags must be all zero or parse_pkg_uflags + * would have failed. + */ + goto exit_free; + } + } + + /* At this point the monr is guaranteed to be this css's monr. */ + monr = monr_from_css(css); + + /* Disregard if flags have not changed. */ + if (!memcmp(uflags, monr->pkg_uflags, pkg_uflags_size)) + goto exit_free; + + /* + * will update monr->pkg_flags. Do not exit on error, continue to + * clean up monr if unused. + */ + err = monr_apply_uflags(monr, uflags); + + if (!monr_has_user(monr)) + monr_destroy(monr); + +exit_free: + kfree(uflags); +exit_unlock: + monr_hrchy_release_mutexes(); + mutex_unlock(&cmt_mutex); + return err ?: nbytes; +} + +struct cftype perf_event_cgrp_arch_subsys_cftypes[] = { + { + /* + * allows per-package specification of uflags. It takes a + * semi-colon separated list of hex uflags values. The hex + * value in the i-th position corresponds to the uflags of + * the package with logical id == i + 1 . Empty and missing hex + * values receive 0. + * e.g. "1;2" -> uflag 0x1 for pkg 0, uflag 0x2 for pkg 2, + * and 0x0 for all others. + */ + .name = "cmt_monitoring", + .seq_show = cmt_monitoring_seq_show, + .write = cmt_monitoring_write, + }, + + {} /* terminate */ +}; + +#endif + device_initcall(intel_cmt_init); diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 783bdbb..babee97 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -315,6 +315,16 @@ int perf_cgroup_arch_css_online(struct cgroup_subsys_state *css); perf_cgroup_arch_css_offline void perf_cgroup_arch_css_offline(struct cgroup_subsys_state *css); +extern struct cftype perf_event_cgrp_arch_subsys_cftypes[]; + +#define PERF_CGROUP_ARCH_CGRP_SUBSYS_ATTS \ + .dfl_cftypes = perf_event_cgrp_arch_subsys_cftypes, \ + .legacy_cftypes = perf_event_cgrp_arch_subsys_cftypes, + +#else + +#define PERF_CGROUP_ARCH_CGRP_SUBSYS_ATTS + #endif #endif -- 2.8.0.rc3.226.g39d4020
|  |