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authorQuentin Monnet <quentin@isovalent.com>2021-07-31 00:54:34 +0300
committerAndrii Nakryiko <andrii@kernel.org>2021-07-31 01:40:28 +0300
commit8cc8c6357c8fa763c650f1bddb69871a254f427c (patch)
tree89c18311172b507277dfbb9cfd45de5d2723b003 /tools/bpf/bpftool/Documentation/bpftool-prog.rst
parentda87772f086fc40e0ced9deb939400b09a182194 (diff)
downloadlinux-8cc8c6357c8fa763c650f1bddb69871a254f427c.tar.xz
tools: bpftool: Document and add bash completion for -L, -B options
The -L|--use-loader option for using loader programs when loading, or when generating a skeleton, did not have any documentation or bash completion. Same thing goes for -B|--base-btf, used to pass a path to a base BTF object for split BTF such as BTF for kernel modules. This patch documents and adds bash completion for those options. Fixes: 75fa1777694c ("tools/bpftool: Add bpftool support for split BTF") Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.") Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210730215435.7095-7-quentin@isovalent.com
Diffstat (limited to 'tools/bpf/bpftool/Documentation/bpftool-prog.rst')
-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-prog.rst30
1 files changed, 29 insertions, 1 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 4b8412fe2c60..2ea5df30ff21 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -13,7 +13,8 @@ SYNOPSIS
**bpftool** [*OPTIONS*] **prog** *COMMAND*
*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-d** | **--debug** } |
- { **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } }
+ { **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
+ { **-L** | **--use-loader** } }
*COMMANDS* :=
{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load**
@@ -224,6 +225,20 @@ OPTIONS
Do not automatically attempt to mount any virtual file system
(such as tracefs or BPF virtual file system) when necessary.
+ -L, --use-loader
+ Load program as a "loader" program. This is useful to debug
+ the generation of such programs. When this option is in
+ use, bpftool attempts to load the programs from the object
+ file into the kernel, but does not pin them (therefore, the
+ *PATH* must not be provided).
+
+ When combined with the **-d**\ \|\ **--debug** option,
+ additional debug messages are generated, and the execution
+ of the loader program will use the **bpf_trace_printk**\ ()
+ helper to log each step of loading BTF, creating the maps,
+ and loading the programs (see **bpftool prog tracelog** as
+ a way to dump those messages).
+
EXAMPLES
========
**# bpftool prog show**
@@ -327,3 +342,16 @@ EXAMPLES
40176203 cycles (83.05%)
42518139 instructions # 1.06 insns per cycle (83.39%)
123 llc_misses # 2.89 LLC misses per million insns (83.15%)
+
+|
+| Output below is for the trace logs.
+| Run in separate terminals:
+| **# bpftool prog tracelog**
+| **# bpftool prog load -L -d file.o**
+
+::
+
+ bpftool-620059 [004] d... 2634685.517903: bpf_trace_printk: btf_load size 665 r=5
+ bpftool-620059 [004] d... 2634685.517912: bpf_trace_printk: map_create sample_map idx 0 type 2 value_size 4 value_btf_id 0 r=6
+ bpftool-620059 [004] d... 2634685.517997: bpf_trace_printk: prog_load sample insn_cnt 13 r=7
+ bpftool-620059 [004] d... 2634685.517999: bpf_trace_printk: close(5) = 0