From: "Wangnan (F)" <wangnan0@huawei.com>
To: Alexei Starovoitov <ast@plumgrid.com>, <acme@kernel.org>,
<brendan.d.gregg@gmail.com>, <daniel@iogearbox.net>,
<namhyung@kernel.org>, <masami.hiramatsu.pt@hitachi.com>,
<paulus@samba.org>, <a.p.zijlstra@chello.nl>, <mingo@redhat.com>,
<jolsa@kernel.org>, <dsahern@gmail.com>
Cc: <linux-kernel@vger.kernel.org>, <lizefan@huawei.com>,
<hekuang@huawei.com>, <xiakaixu@huawei.com>, <pi3orama@163.com>
Subject: Re: [RFC PATCH v6 25/32] perf tools: Add 'bpf.' config section to perf default config
Date: Wed, 10 Jun 2015 08:47:24 +0800 [thread overview]
Message-ID: <5577891C.5010904@huawei.com> (raw)
In-Reply-To: <55777A17.7030000@plumgrid.com>
On 2015/6/10 7:43, Alexei Starovoitov wrote:
> On 6/8/15 10:50 PM, Wang Nan wrote:
>> perf_bpf_config() is added to parse 'bpf' section in perf config file.
>> Following is an example:
>>
>> [bpf]
>> clang-path = /llvm/bin/x86_64-linux-clang"
>> llc-path = /llvm/bin/x86_64-linux-llc"
>> clang-opt = "-nostdinc -isystem /llvm/lib/clang/include
>> -I/kernel/arch/x86/include ..."
>> llc-opt = ""
>
> a section to specify -I flags to compile prog.c is useful,
> but users shouldn't be populating it manually for kernel headers.
> How about adding a script that can figure out $(LINUXINCLUDE)
> automatically ?
> You can even invoke such flag detector from perf via something like:
> f = open /tmpdir/Makefile
> fprintf(f, "obj-y := dummy.o\n");
> fprintf(f, "$(obj)/%%.o: $(src)/%%.c\n");
> fprintf(f, "\t@echo -n \"$(NOSTDINC_FLAGS) $(LINUXINCLUDE)
> $(EXTRA_CFLAGS)\" > %s\n", cachefile);
> snprintf(cmd, "make -s -C /lib/modules/%s/build M=%s dummy.o",
> uts_release, tmpdir);
> system(cmd);
> read flags from cachefile and cache it for the future.
> ...
> or as independent script that populates .perfconfig
>
That's cool, but could I implement it later? Introducing such stuffs
also introduces
a lot of trouble tasks:
1. Dependency on make and kernel build. We should search make and kbuild
dir dynamically
and also gives users the right to specify them by theirselves. A lot
of configuration
options should be appended: --make-path=/path/to/make
--kbuild-dir=kernel/build/dir
in cmdline and
[kbuild]
make_path = /path/to/make
kbuild_dir = /path/to/kbuild
in .perfconfig.
2. Selection of architectures. Although currently we want it to work
only when we dynamically
compile a script, I think finally we should consider cross compiling
bpf objects. Then cmdline
generation becomes complex. Also, --arch and [kbuild.arch] should
also be introduced.
3. Kernel dependency. Consider if kernel decides to change its interface...
I think currently we can pop some messages to let user know how to get
include dirs manually,
let further patches to do it for them automatically.
P.S.
Have you tested your Makefile? It doesn't work for me:
# cat ./Makefile
obj-y := dummy.o
$(obj)/%.o: $(src)/%.c
@echo -n "$(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS)" > xxxx
# make -s -C kernel/build/dir M=`pwd` dummy.o
make[2]: *** No rule to make target `dummy.o'. Stop.
make[1]: *** [sub-make] Error 2
make: *** [__sub-make] Error 2
Thank you.
next prev parent reply other threads:[~2015-06-10 0:55 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-09 5:50 [RFC PATCH v6 00/32] perf tools: filtering events using eBPF programs Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 01/32] tools build: Add feature check for eBPF API Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 02/32] bpf tools: Introduce 'bpf' library to tools Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 03/32] bpf tools: Allow caller to set printing function Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 04/32] bpf tools: Open eBPF object file and do basic validation Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 05/32] bpf tools: Read eBPF object from buffer Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 06/32] bpf tools: Check endianess and make libbpf fail early Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 07/32] bpf tools: Iterate over ELF sections to collect information Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 08/32] bpf tools: Collect version and license from ELF sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 09/32] bpf tools: Collect map definitions from 'maps' section Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 10/32] bpf tools: Collect symbol table from SHT_SYMTAB section Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 11/32] bpf tools: Collect eBPF programs from their own sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 12/32] bpf tools: Collect relocation sections from SHT_REL sections Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 13/32] bpf tools: Record map accessing instructions for each program Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 14/32] bpf tools: Add bpf.c/h for common bpf operations Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 15/32] bpf tools: Create eBPF maps defined in an object file Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 16/32] bpf tools: Relocate eBPF programs Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 17/32] bpf tools: Introduce bpf_load_program() to bpf.c Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 18/32] bpf tools: Load eBPF programs in object files into kernel Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 19/32] bpf tools: Introduce accessors for struct bpf_program Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 20/32] bpf tools: Introduce accessors for struct bpf_object Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 21/32] bpf tools: Link all bpf objects onto a list Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 22/32] perf tools: Make perf depend on libbpf Wang Nan
2015-06-09 10:29 ` Wangnan (F)
2015-06-09 5:50 ` [RFC PATCH v6 23/32] perf record: Enable passing bpf object file to --event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 24/32] perf record: Compile scriptlets if pass '.c' " Wang Nan
2015-06-09 21:48 ` Alexei Starovoitov
2015-06-10 0:06 ` Wangnan (F)
2015-06-10 0:28 ` Alexei Starovoitov
2015-06-11 7:19 ` Namhyung Kim
2015-06-11 7:35 ` Wangnan (F)
2015-06-11 17:42 ` Alexei Starovoitov
2015-06-09 5:50 ` [RFC PATCH v6 25/32] perf tools: Add 'bpf.' config section to perf default config Wang Nan
2015-06-09 23:43 ` Alexei Starovoitov
2015-06-10 0:47 ` Wangnan (F) [this message]
2015-06-10 1:09 ` Alexei Starovoitov
2015-06-10 2:23 ` Wangnan (F)
2015-06-10 3:55 ` Alexei Starovoitov
2015-06-11 7:45 ` Namhyung Kim
2015-06-11 8:09 ` Wangnan (F)
2015-06-11 14:50 ` Namhyung Kim
2015-06-09 5:50 ` [RFC PATCH v6 26/32] perf tools: Parse probe points of eBPF programs during preparation Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 27/32] perf probe: Attach trace_probe_event with perf_probe_event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 28/32] perf record: Probe at kprobe points Wang Nan
2015-06-11 14:32 ` Namhyung Kim
2015-06-09 5:50 ` [RFC PATCH v6 29/32] perf record: Load all eBPF object into kernel Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 30/32] perf tools: Add bpf_fd field to evsel and config it Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 31/32] perf tools: Attach eBPF program to perf event Wang Nan
2015-06-09 5:50 ` [RFC PATCH v6 32/32] perf record: Add LLVM options for compiling BPF scripts Wang Nan
2015-06-09 13:32 ` Wangnan (F)
2015-06-10 0:02 ` Alexei Starovoitov
2015-06-10 0:17 ` Wangnan (F)
2015-06-10 1:34 ` Alexei Starovoitov
2015-06-09 13:59 ` [RFC PATCH v6 00/32] perf tools: filtering events using eBPF programs Arnaldo Carvalho de Melo
2015-06-09 23:45 ` Wangnan (F)
2015-06-09 21:30 ` Alexei Starovoitov
2015-06-09 21:44 ` Arnaldo Carvalho de Melo
2015-06-09 23:16 ` Alexei Starovoitov
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