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Subject: Re: [PATCH 3/3] x86/ftrace: Use text_poke()
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        Nadav Amit <nadav.amit@gmail.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Song Liu <songliubraving@fb.com>,
        Masami Hiramatsu <mhiramat@kernel.org>
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 <20190827181147.166658077@infradead.org>
 <aaffb32f-6ca9-f9e3-9b1a-627125c563ed@redhat.com>
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 <20191003181045.7fb1a5b3@gandalf.local.home>
 <7b4196a4-b6e1-7e55-c3e1-a02d97c262c7@redhat.com>
 <20191004094014.72a990ee@gandalf.local.home>
From:   Daniel Bristot de Oliveira <bristot@redhat.com>
Message-ID: <761c5baf-598d-c2da-bd3e-2a669bf16b50@redhat.com>
Date:   Fri, 4 Oct 2019 16:44:35 +0200
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On 04/10/2019 15:40, Steven Rostedt wrote:
> On Fri, 4 Oct 2019 10:10:47 +0200
> Daniel Bristot de Oliveira <bristot@redhat.com> wrote:
>=20
>> [ In addition ]
>>
>> Currently, ftrace_rec entries are ordered inside the group of functions,=
 but
>> "groups of function" are not ordered. So, the current int3 handler does =
a (*):
>>
>> for_each_group_of_functions:
>> =09check if the ip is in the range    ----> n by the number of groups.
>> =09=09do a bsearch.=09=09   ----> log(n) by the numbers of entry
>> =09=09=09=09=09         in the group.
>>
>> If, instead, it uses an ordered vector, the complexity would be log(n) b=
y the
>> total number of entries, which is better. So, how bad is the idea of:
> BTW, I'm currently rewriting the grouping of the vectors, in order to
> shrink the size of each dyn_ftrace_rec (as we discussed at Kernel
> Recipes). I can make the groups all sorted in doing so, thus we can
> load the sorted if that's needed, without doing anything special.
>=20

Good! if you do they sorted and store the amount of entries in a variable, =
we
can have things done for a future "optimized" version.

-- Daniel