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| author | Alexei Starovoitov | 2015-03-25 20:49:25 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2015-04-02 13:25:51 +0200 |
| commit | 5c7fc2d27d004f28f3a94b35edd40e68f779e35a (patch) | |
| tree | 97eb95fe90f8902117327038f4e1dadaf5c0ea43 /samples/bpf/Makefile | |
| parent | samples/bpf: Add counting example for kfree_skb() function calls and the writ... (diff) | |
| download | kernel-qcow2-linux-5c7fc2d27d004f28f3a94b35edd40e68f779e35a.tar.gz kernel-qcow2-linux-5c7fc2d27d004f28f3a94b35edd40e68f779e35a.tar.xz kernel-qcow2-linux-5c7fc2d27d004f28f3a94b35edd40e68f779e35a.zip | |
samples/bpf: Add IO latency analysis (iosnoop/heatmap) tool
BPF C program attaches to
blk_mq_start_request()/blk_update_request() kprobe events to
calculate IO latency.
For every completed block IO event it computes the time delta
in nsec and records in a histogram map:
map[log10(delta)*10]++
User space reads this histogram map every 2 seconds and prints
it as a 'heatmap' using gray shades of text terminal. Black
spaces have many events and white spaces have very few events.
Left most space is the smallest latency, right most space is
the largest latency in the range.
Usage:
$ sudo ./tracex3
and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal.
Observe IO latencies and how different activity (like 'make
kernel') affects it.
Similar experiments can be done for network transmit latencies,
syscalls, etc.
'-t' flag prints the heatmap using normal ascii characters:
$ sudo ./tracex3 -t
heatmap of IO latency
# - many events with this latency
- few events
|1us |10us |100us |1ms |10ms |100ms |1s |10s
*ooo. *O.#. # 221
. *# . # 125
.. .o#*.. # 55
. . . . .#O # 37
.# # 175
.#*. # 37
# # 199
. . *#*. # 55
*#..* # 42
# # 266
...***Oo#*OO**o#* . # 629
# # 271
. .#o* o.*o* # 221
. . o* *#O.. # 50
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'samples/bpf/Makefile')
| -rw-r--r-- | samples/bpf/Makefile | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 6dd272143733..dcd850546d52 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -8,6 +8,7 @@ hostprogs-y += sockex1 hostprogs-y += sockex2 hostprogs-y += tracex1 hostprogs-y += tracex2 +hostprogs-y += tracex3 test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -16,6 +17,7 @@ sockex1-objs := bpf_load.o libbpf.o sockex1_user.o sockex2-objs := bpf_load.o libbpf.o sockex2_user.o tracex1-objs := bpf_load.o libbpf.o tracex1_user.o tracex2-objs := bpf_load.o libbpf.o tracex2_user.o +tracex3-objs := bpf_load.o libbpf.o tracex3_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -23,6 +25,7 @@ always += sockex1_kern.o always += sockex2_kern.o always += tracex1_kern.o always += tracex2_kern.o +always += tracex3_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -31,6 +34,7 @@ HOSTLOADLIBES_sockex1 += -lelf HOSTLOADLIBES_sockex2 += -lelf HOSTLOADLIBES_tracex1 += -lelf HOSTLOADLIBES_tracex2 += -lelf +HOSTLOADLIBES_tracex3 += -lelf # point this to your LLVM backend with bpf support LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc |