06 Feb, 2016
1 commit
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Signed-off-by: Alexei Starovoitov
Signed-off-by: David S. Miller
09 Jul, 2015
1 commit
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The trace bpf samples do not compile on s390x because they use x86
specific fields from the "pt_regs" structure.Fix this and access the fields via new PT_REGS macros.
Signed-off-by: Michael Holzheu
Acked-by: Alexei Starovoitov
Signed-off-by: David S. Miller
02 Apr, 2015
1 commit
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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.. # 50Signed-off-by: Alexei Starovoitov
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Daniel Borkmann
Cc: David S. Miller
Cc: Jiri Olsa
Cc: Linus Torvalds
Cc: Masami Hiramatsu
Cc: Namhyung Kim
Cc: Peter Zijlstra
Cc: Peter Zijlstra
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com
Signed-off-by: Ingo Molnar
