From: David S. Miller Date: Mon, 10 Aug 2015 05:50:06 +0000 (-0700) Subject: Merge branch 'bpf-perf' X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=d74a790d5237e7f56677030d932bc4f37ec36c92;p=openwrt%2Fstaging%2Fblogic.git Merge branch 'bpf-perf' Kaixu Xia says: ==================== bpf: Introduce the new ability of eBPF programs to access hardware PMU counter This patchset is base on the net-next: git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git commit 9dc20a649609c95ce7c5ac4282656ba627b67d49. Previous patch v6 url: https://lkml.org/lkml/2015/8/4/188 changes in V7: - rebase the whole patch set to net-next tree(9dc20a64); - split out the core perf APIs into Patch 1/5; - change the return value of function perf_event_attrs() from struct perf_event * to const struct perf_event * in Patch 1/5; - rename the function perf_event_read_internal() to perf_event_ read_local() and rewrite it in Patch 1/5; - rename the function check_func_limit() to check_map_func _compatibility() and remove the unnecessary pass pointer to a pointer in Patch 4/5; changes in V6: - make the Patch 1/4 commit message more meaning and readable; - remove the unnecessary comment in Patch 2/4 and make it clean; - declare the function perf_event_release_kernel() in include/ linux/perf_event.h to fix the build error when CONFIG_PERF_EVENTS isn't configured in Patch 2/4; - add function perf_event_attrs() to get the struct perf_event_attr in Patch 2/4. - move the related code from kernel/trace/bpf_trace.c to kernel/ events/core.c and add function perf_event_read_internal() to avoid poking inside of the event outside of perf code in Patch 3/4; - generial the func & map match-pair with an array in Patch 3/4; changes in V5: - move struct fd_array_map_ops* fd_ops to bpf_map; - move array perf event decrement refcnt function to map_free; - fix the NULL ptr of perf_event_get(); - move bpf_perf_event_read() to kernel/bpf/bpf_trace.c; - get rid of the remaining struct bpf_prog; - move the unnecessay cast on void *; changes in V4: - make the bpf_prog_array_map more generic; - fix the bug of event refcnt leak; - use more useful errno in bpf_perf_event_read(); changes in V3: - collapse V2 patches 1-3 into one; - drop the function map->ops->map_traverse_elem() and release the struct perf_event in map_free; - only allow to access bpf_perf_event_read() from programs; - update the perf_event_array_map elem via xchg(); - pass index directly to bpf_perf_event_read() instead of MAP_KEY; changes in V2: - put atomic_long_inc_not_zero() between fdget() and fdput(); - limit the event type to PERF_TYPE_RAW and PERF_TYPE_HARDWARE; - Only read the event counter on current CPU or on current process; - add new map type BPF_MAP_TYPE_PERF_EVENT_ARRAY to store the pointer to the struct perf_event; - according to the perf_event_map_fd and key, the function bpf_perf_event_read() can get the Hardware PMU counter value; Patch 5/5 is a simple example and shows how to use this new eBPF programs ability. The PMU counter data can be found in /sys/kernel/debug/tracing/trace(trace_pipe).(the cycles PMU value when 'kprobe/sys_write' sampling) $ cat /sys/kernel/debug/tracing/trace_pipe $ ./tracex6 ... syslog-ng-548 [000] d..1 76.905673: : CPU-0 681765271 syslog-ng-548 [000] d..1 76.905690: : CPU-0 681787855 syslog-ng-548 [000] d..1 76.905707: : CPU-0 681810504 syslog-ng-548 [000] d..1 76.905725: : CPU-0 681834771 syslog-ng-548 [000] d..1 76.905745: : CPU-0 681859519 syslog-ng-548 [000] d..1 76.905766: : CPU-0 681890419 syslog-ng-548 [000] d..1 76.905783: : CPU-0 681914045 syslog-ng-548 [000] d..1 76.905800: : CPU-0 681935950 syslog-ng-548 [000] d..1 76.905816: : CPU-0 681958299 ls-690 [005] d..1 82.241308: : CPU-5 3138451 sh-691 [004] d..1 82.244570: : CPU-4 7324988 <...>-699 [007] d..1 99.961387: : CPU-7 3194027 <...>-695 [003] d..1 99.961474: : CPU-3 288901 <...>-695 [003] d..1 99.961541: : CPU-3 383145 <...>-695 [003] d..1 99.961591: : CPU-3 450365 <...>-695 [003] d..1 99.961639: : CPU-3 515751 <...>-695 [003] d..1 99.961686: : CPU-3 579047 ... The detail of patches is as follow: Patch 1/5 add the necessary core perf APIs perf_event_attrs(), perf_event_get(),perf_event_read_local() when accessing events counters in eBPF programs Patch 2/5 rewrites part of the bpf_prog_array map code and make it more generic; Patch 3/5 introduces a new bpf map type. This map only stores the pointer to struct perf_event; Patch 4/5 implements function bpf_perf_event_read() that get the selected hardware PMU conuter; Patch 5/5 gives a simple example. ==================== Signed-off-by: David S. Miller --- d74a790d5237e7f56677030d932bc4f37ec36c92