From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-kbuild@vger.kernel.org, bpf <bpf@vger.kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nicolas@fjasle.eu>,
Zheng Yejian <zhengyejian1@huawei.com>,
Martin Kelly <martin.kelly@crowdstrike.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 14/14] scripts/sorttable: ftrace: Do not add weak functions to available_filter_functions
Date: Thu, 2 Jan 2025 21:36:25 +0100 [thread overview]
Message-ID: <20250102203625.GF7274@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20250102153016.7fc5e443@gandalf.local.home>
On Thu, Jan 02, 2025 at 03:30:16PM -0500, Steven Rostedt wrote:
> On Thu, 2 Jan 2025 21:24:04 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > It is not. If kallsyms is fixed, you can use that to tell which
> > fentry/mcount sites are 'invalid'.
>
> I can't use kallsyms for valid tests at boot up. Even with a binary search,
> it's still rather slow. The ftrace table is created at early boot, even
> before scheduling (it's needed before you can enable boot time function
> tracing), so any slow down in creating that table slows down the boot, and
> people will notice.
I'm not sure I understand, up until you've started userspace, nobody
cares about those weird indexes.
next prev parent reply other threads:[~2025-01-02 20:36 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-02 18:58 [PATCH 00/14] scripts/sorttable: ftrace: Remove place holders for weak functions in available_filter_functions Steven Rostedt
2025-01-02 18:58 ` [PATCH 01/14] scripts/sorttable: Remove unused macro defines Steven Rostedt
2025-01-02 18:58 ` [PATCH 02/14] scripts/sorttable: Remove unused write functions Steven Rostedt
2025-01-02 18:58 ` [PATCH 03/14] scripts/sorttable: Remove unneeded Elf_Rel Steven Rostedt
2025-01-02 18:58 ` [PATCH 04/14] scripts/sorttable: Have the ORC code use the _r() functions to read Steven Rostedt
2025-01-02 18:58 ` [PATCH 05/14] scripts/sorttable: Make compare_extable() into two functions Steven Rostedt
2025-01-02 18:58 ` [PATCH 06/14] scripts/sorttable: Convert Elf_Ehdr to union Steven Rostedt
2025-01-02 18:58 ` [PATCH 07/14] scripts/sorttable: Replace Elf_Shdr Macro with a union Steven Rostedt
2025-01-02 18:58 ` [PATCH 08/14] scripts/sorttable: Convert Elf_Sym MACRO over to " Steven Rostedt
2025-01-02 18:58 ` [PATCH 09/14] scripts/sorttable: Add helper functions for Elf_Ehdr Steven Rostedt
2025-01-02 18:58 ` [PATCH 10/14] scripts/sorttable: Add helper functions for Elf_Shdr Steven Rostedt
2025-01-02 18:58 ` [PATCH 11/14] scripts/sorttable: Add helper functions for Elf_Sym Steven Rostedt
2025-01-02 18:58 ` [PATCH 12/14] scripts/sorttable: Use uint64_t for mcount sorting Steven Rostedt
2025-01-02 18:58 ` [PATCH 13/14] scripts/sorttable: Move code from sorttable.h into sorttable.c Steven Rostedt
2025-01-02 18:58 ` [PATCH 14/14] scripts/sorttable: ftrace: Do not add weak functions to available_filter_functions Steven Rostedt
2025-01-02 19:48 ` Peter Zijlstra
2025-01-02 19:55 ` Steven Rostedt
2025-01-02 20:03 ` Steven Rostedt
2025-01-02 20:32 ` Peter Zijlstra
2025-01-02 20:41 ` Steven Rostedt
2025-01-02 20:48 ` Peter Zijlstra
2025-01-02 20:53 ` Steven Rostedt
2025-01-02 20:24 ` Peter Zijlstra
2025-01-02 20:30 ` Steven Rostedt
2025-01-02 20:36 ` Peter Zijlstra [this message]
2025-01-02 20:45 ` Steven Rostedt
2025-01-03 11:10 ` Jiri Olsa
2025-01-03 11:41 ` Peter Zijlstra
2025-01-03 12:14 ` Steven Rostedt
2025-01-03 18:06 ` Jiri Olsa
2025-01-02 19:24 ` [PATCH 00/14] scripts/sorttable: ftrace: Remove place holders for weak functions in available_filter_functions Steven Rostedt
2025-01-02 19:30 ` Linus Torvalds
2025-01-02 19:45 ` Steven Rostedt
2025-01-02 19:47 ` Steven Rostedt
2025-01-02 21:44 ` Steven Rostedt
2025-01-02 22:14 ` Steven Rostedt
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