From: Masami Hiramatsu <mhiramat@kernel.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: acme@kernel.org, jolsa@kernel.org, mhiramat@kernel.org,
adrian.hunter@intel.com, linux-kernel@vger.kernel.org
Subject: Re: Implement dwarf variable/type resolving for perf script
Date: Tue, 28 Nov 2017 14:31:00 +0900 [thread overview]
Message-ID: <20171128143100.e23ce8a6a592bbb1b51cda19@kernel.org> (raw)
In-Reply-To: <20171128002321.2878-1-andi@firstfloor.org>
Hi Andi,
On Mon, 27 Nov 2017 16:23:09 -0800
Andi Kleen <andi@firstfloor.org> wrote:
> This patchkit extends perf script to query dwarf information for variable
> names or types/structure fields accessed from code.
Very interesting! so it is a kind of revert query interface.
>
> The dwarf resolution is all on top of Masami's perf probe dwarf code.
>
> It supports multiple use cases:
> - When we sample registers it can use the dwarf information to resolve
> the registers to names.
> - When we sample any instruction the instruction can be decoded and
> we can determine the type/struct field to make an estimate of the
> memory access patterns in data structures.
> - When we sample the new PTWRITE instruction the logged value from
> the PT log can be associated with a variable.
> - Various cleanups and fixes to make the one above all possible.
OK, I'll review that.
Thanks!
>
> It is all implemented with new output formats in perf script:
> iregval (map register values to names) and insnvar (decode instruction
> and map back memory operand to dwarf operation)
>
> There are some limitations, it cannot decode everything, and is
> somewhat slow, but it's already quite useful for typical code
>
>
> % perf record -Idi,si ./targ
> % perf script -F +iregvals
> ...
> targ 8584 169763.761843: 2091795 cycles:ppp: 40041a main (targ)
> targ 8584 169763.762520: 1913932 cycles:ppp: 400534 f1 (targ) { b = 0x2, int } { a = 0x1, int }
> targ 8584 169763.763141: 1638913 cycles:ppp: 400523 f2 (targ) { b = 0x1, int } { a = 0x2, int }
> targ 8584 169763.763672: 1516522 cycles:ppp: 400522 f2 (targ) { b = 0x1, int } { a = 0x2, int }
> targ 8584 169763.764165: 1335501 cycles:ppp: 400523 f2 (targ) { b = 0x1, int } { a = 0x2, int }
> targ 8584 169763.764598: 1253289 cycles:ppp: 400522 f2 (targ) { b = 0x2, int } { a = 0x1, int }
> targ 8584 169763.765005: 1135131 cycles:ppp: 400534 f1 (targ) { b = 0x2, int } { a = 0x1, int }
> targ 8584 169763.765373: 1080325 cycles:ppp: 400522 f2 (targ) { b = 0x2, int } { a = 0x1, int }
> targ 8584 169763.765724: 1036999 cycles:ppp: 400522 f2 (targ) { b = 0x1, int } { a = 0x2, int }
> targ 8584 169763.766061: 971213 cycles:ppp: 400534 f1 (targ) { b = 0x2, int } { a = 0x1, int }
>
>
> % perf record -e intel_pt//u -a sleep 1
> % perf script --itrace=i0ns -F insnvar,insn,ip,sym -f 2>&1 | xed -F insn: -A -64 | less
> ...
> 4f7e61 xyarray__max_y pushq %rbp
> 4f7e62 xyarray__max_y mov %rsp, %rbp
> 4f7e65 xyarray__max_y sub $0x20, %rsp
> 4f7e69 xyarray__max_y movq %rdi, -0x18(%rbp) { -24(xy), struct xyarray* }
> 4f7e6d xyarray__max_y movq %fs:0x28, %rax
> 4f7e76 xyarray__max_y movq %rax, -0x8(%rbp) { -8(xy), struct xyarray* }
> 4f7e7a xyarray__max_y xor %eax, %eax
> 4f7e7c xyarray__max_y movq -0x18(%rbp), %rax { -24(xy), struct xyarray* }
> 4f7e80 xyarray__max_y movq 0x20(%rax), %rax
> 4f7e84 xyarray__max_y movq -0x8(%rbp), %rdx { -8(xy), struct xyarray* }
> 4f7e88 xyarray__max_y xorq %fs:0x28, %rdx
> 4f7e91 xyarray__max_y jz 0x7
> 4f7e98 xyarray__max_y leaveq
> 4f7e99 xyarray__max_y retq
>
> In this example we now know that this function accesses two fields in struct xyarray *
>
> Available from
>
> git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc perf/var-resolve-2
>
> v1: Initial post
--
Masami Hiramatsu <mhiramat@kernel.org>
prev parent reply other threads:[~2017-11-28 5:31 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-28 0:23 Implement dwarf variable/type resolving for perf script Andi Kleen
2017-11-28 0:23 ` [PATCH 01/12] perf, tools, pt: Clear instruction for ptwrite samples Andi Kleen
2017-11-28 0:23 ` [PATCH 02/12] perf, tools, script: Print insn/insnlen for non PT sample Andi Kleen
2017-11-28 0:23 ` [PATCH 03/12] perf, tools: Support storing additional data in strlist Andi Kleen
2017-11-28 13:31 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 04/12] perf, tools: Store variable name and register for dwarf variable lists Andi Kleen
2017-11-28 0:23 ` [PATCH 05/12] perf, tools, probe: Print location for resolved variables Andi Kleen
2017-11-29 1:19 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 06/12] perf, tools, probe: Support a quiet argument for debug info open Andi Kleen
2017-11-29 3:14 ` Masami Hiramatsu
2017-11-29 3:39 ` Andi Kleen
2017-11-30 2:36 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 07/12] perf, tools, script: Resolve variable names for registers Andi Kleen
2017-11-28 0:23 ` [PATCH 08/12] perf, tools: Always print probe finder warnings with -v Andi Kleen
2017-11-29 3:16 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 09/12] perf, tools: Downgrade register mapping message to warning Andi Kleen
2017-11-29 5:56 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 10/12] perf, tools: Add args and gprs shortcut for registers Andi Kleen
2017-11-28 0:23 ` [PATCH 11/12] perf, tools: Print probe warnings for binaries only once per binary Andi Kleen
2017-11-30 2:38 ` Masami Hiramatsu
2017-11-28 0:23 ` [PATCH 12/12] perf, tools, script: Implement dwarf resolving of instructions Andi Kleen
2017-12-01 2:36 ` Masami Hiramatsu
2017-11-28 5:31 ` Masami Hiramatsu [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171128143100.e23ce8a6a592bbb1b51cda19@kernel.org \
--to=mhiramat@kernel.org \
--cc=acme@kernel.org \
--cc=adrian.hunter@intel.com \
--cc=andi@firstfloor.org \
--cc=jolsa@kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.