From: Sven Schnelle <svens@linux.ibm.com>
To: Yinan Liu <yinan@linux.alibaba.com>
Cc: rostedt@goodmis.org, peterz@infradead.org,
mark-pk.tsai@mediatek.com, mingo@redhat.com,
linux-kernel@vger.kernel.org, hca@linux.ibm.com,
linux-s390@vger.kernel.org
Subject: Re: [PATCH v8] scripts: ftrace - move the sort-processing in ftrace_init
Date: Fri, 21 Jan 2022 10:46:36 +0100 [thread overview]
Message-ID: <yt9dee51ctfn.fsf@linux.ibm.com> (raw)
In-Reply-To: <20211212113358.34208-2-yinan@linux.alibaba.com> (Yinan Liu's message of "Sun, 12 Dec 2021 19:33:58 +0800")
Hi Yinan,
Yinan Liu <yinan@linux.alibaba.com> writes:
> When the kernel starts, the initialization of ftrace takes
> up a portion of the time (approximately 6~8ms) to sort mcount
> addresses. We can save this time by moving mcount-sorting to
> compile time.
>
> Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: kernel test robot <oliver.sang@intel.com>
> ---
> kernel/trace/ftrace.c | 11 +++-
> scripts/Makefile | 6 +-
> scripts/link-vmlinux.sh | 6 +-
> scripts/sorttable.c | 2 +
> scripts/sorttable.h | 120 +++++++++++++++++++++++++++++++++++++++-
> 5 files changed, 137 insertions(+), 8 deletions(-)
while i like the idea, this unfortunately breaks ftrace on s390. The
reason for that is that the compiler generates relocation entries for
all the addresses in __mcount_loc. During boot, the s390 decompressor
iterates through all the relocations and overwrites the nicely
sorted list between __start_mcount_loc and __stop_mcount_loc with
the unsorted list because the relocations entries are not adjusted.
Of course we could just disable that option, but that would make us
different compared to x86 which i don't like. Adding code to sort the
relocation would of course also fix that, but i don't think it is a good
idea to rely on the order of relocations.
Any thoughts how a fix could look like, and whether that could also be a
problem on other architectures?
Thanks
Sven
next prev parent reply other threads:[~2022-01-21 9:47 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 13:50 [PATCH 0/2] ftrace: improve ftrace during compiling Yinan Liu
2021-09-11 13:50 ` [PATCH 1/2] scripts: ftrace - move the sort-processing in ftrace_init to compile time Yinan Liu
2021-09-11 13:59 ` Steven Rostedt
2021-10-03 13:42 ` Yinan Liu
2021-10-08 23:48 ` Steven Rostedt
2021-10-09 2:56 ` Yinan Liu
2021-10-25 13:20 ` Yinan Liu
2021-10-25 15:00 ` Steven Rostedt
2021-09-11 13:50 ` [PATCH 2/2] scripts: ftrace - move the nop-processing " Yinan Liu
2021-09-11 14:12 ` Steven Rostedt
2021-09-11 15:28 ` Yinan Liu
2021-09-11 16:07 ` Peter Zijlstra
2021-09-11 14:33 ` Peter Zijlstra
2021-09-11 17:15 ` kernel test robot
2021-09-11 18:04 ` kernel test robot
2021-11-16 2:49 ` [PATCH v2 0/2] ftrace optimization at " Yinan Liu
2021-11-16 2:49 ` [PATCH v2 1/2] scripts: ftrace - move the sort-processing in ftrace_init to " Yinan Liu
2021-11-16 8:07 ` Peter Zijlstra
2021-11-16 12:42 ` Yinan Liu
2021-11-16 13:05 ` Peter Zijlstra
2021-11-16 14:46 ` Yinan Liu
2021-11-17 13:34 ` kernel test robot
2021-11-16 2:49 ` [PATCH v2 2/2] scripts: ftrace - move the nop-processing " Yinan Liu
2021-11-16 8:10 ` Peter Zijlstra
2021-11-16 12:51 ` Yinan Liu
2021-11-16 13:07 ` Steven Rostedt
2021-11-16 15:02 ` Yinan Liu
2021-11-16 16:06 ` Steven Rostedt
2021-11-22 13:43 ` [PATCH v3] scripts: ftrace - move the sort-processing " Yinan Liu
2021-11-23 10:54 ` [PATCH v4] ftrace sorting optimization changelog Yinan Liu
2021-11-23 10:54 ` [PATCH v4] scripts: ftrace - move the sort-processing in ftrace_init to compile time Yinan Liu
2021-11-29 2:13 ` Yinan Liu
2021-11-29 3:51 ` Steven Rostedt
2021-11-29 6:52 ` Yinan Liu
2021-11-30 17:08 ` Steven Rostedt
2021-12-01 5:32 ` [PATCH v5 0/2] ftrace sorting optimization changelog Yinan Liu
2021-12-01 5:32 ` [PATCH v5 1/2] scripts: ftrace - move the sort-processing in ftrace_init to compile time Yinan Liu
2021-12-01 21:45 ` Steven Rostedt
2021-12-05 12:35 ` [scripts] 12955fb1c5: kernel-selftests.livepatch.test-ftrace.sh.fail kernel test robot
2021-12-01 5:32 ` [PATCH v5 2/2] script/sorttable: code style improvements Yinan Liu
2021-12-02 2:16 ` [PATCH v6 0/2] ftrace sorting optimization changelog Yinan Liu
2021-12-02 2:16 ` [PATCH v6 1/2] scripts: ftrace - move the sort-processing in ftrace_init Yinan Liu
2021-12-02 17:58 ` Steven Rostedt
2021-12-05 12:45 ` Masami Hiramatsu
2021-12-06 20:18 ` Steven Rostedt
2021-12-07 1:29 ` Yinan Liu
2021-12-02 2:16 ` [PATCH v6 2/2] script/sorttable: code style improvements Yinan Liu
2021-12-02 15:30 ` [PATCH v6 0/2] ftrace sorting optimization changelog Peter Zijlstra
2021-12-07 15:13 ` [PATCH v7 0/2] ftrace sorting optimization Yinan Liu
2021-12-07 15:13 ` [PATCH v7 1/2] scripts: ftrace - move the sort-processing in ftrace_init Yinan Liu
2021-12-11 14:50 ` Steven Rostedt
2021-12-07 15:13 ` [PATCH v7 2/2] script/sorttable: code style improvements Yinan Liu
2021-12-12 11:33 ` [PATCH v8 0/1] change log Yinan Liu
2021-12-12 11:33 ` [PATCH v8] scripts: ftrace - move the sort-processing in ftrace_init Yinan Liu
2022-01-21 9:46 ` Sven Schnelle [this message]
2022-01-21 10:42 ` Heiko Carstens
2022-01-21 11:14 ` Sven Schnelle
2022-01-21 11:29 ` Sven Schnelle
2022-01-21 18:11 ` Steven Rostedt
2022-01-22 9:17 ` Heiko Carstens
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=yt9dee51ctfn.fsf@linux.ibm.com \
--to=svens@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=mark-pk.tsai@mediatek.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=yinan@linux.alibaba.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).