From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Qu Wenruo <wqu@suse.com>,
linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH v3] tools/lib/traceevent, perf tools: Handle %pU format correctly
Date: Mon, 21 Oct 2019 22:30:37 +0800 [thread overview]
Message-ID: <6bc13ae1-9f26-afaa-ddfa-f1dd1cdcf6df@gmx.com> (raw)
In-Reply-To: <20191021102408.3bb4aa8b@gandalf.local.home>
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On 2019/10/21 下午10:24, Steven Rostedt wrote:
> On Mon, 21 Oct 2019 22:03:21 +0800
> Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>> On 2019/10/21 下午9:56, Steven Rostedt wrote:
>>> On Mon, 21 Oct 2019 17:47:30 +0800
>>> Qu Wenruo <wqu@suse.com> wrote:
>>>
>>>> +static void print_uuid_arg(struct trace_seq *s, void *data, int size,
>>>> + struct tep_event *event, struct tep_print_arg *arg)
>>>> +{
>>>> + unsigned char *buf;
>>>> + int i;
>>>> +
>>>> + if (arg->type != TEP_PRINT_FIELD) {
>>>> + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type);
>>>> + return;
>>>> + }
>>>> +
>>>> + if (!arg->field.field) {
>>>> + arg->field.field = tep_find_any_field(event, arg->field.name);
>>>> + if (!arg->field.field) {
>>>> + do_warning("%s: field %s not found",
>>>> + __func__, arg->field.name);
>>>> + return;
>>>> + }
>>>> + }
>>>> + if (arg->field.field->size < 16) {
>>>> + trace_seq_printf(s, "INVALID UUID: size have %u expect 16",
>>>> + arg->field.field->size);
>>>> + return;
>>>> + }
>>>> + buf = data + arg->field.field->offset;
>>>> +
>>>> + for (i = 0; i < 8; i++) {
>>>> + trace_seq_printf(s, "%02x", buf[2 * i]);
>>>> + trace_seq_printf(s, "%02x", buf[2 * i + 1]);
>>>> + if (1 <= i && i <= 4)
>>>
>>> I'm fine with this patch except for one nit. The above is hard to read
>>> (in my opinion), and I absolutely hate the "constant" compare to
>>> "variable" notation. Please change the above to:
>>>
>>> if (i >= 1 && i <= 4)
>>
>> Isn't this ( 1 <= i && i <= 4 ) easier to find out the lower and upper
>> boundary? only two numbers, both at the end of the expression.
>
> I don't read it like that.
>
>>
>> I feel that ( i >= 1 && i <= 4 ) easier to write, but takes me extra
>> half second to read, thus I changed to the current one.
>
> How do you read it in English?
How about mathematics interval?
i in [1, 4].
It looks way easier and simpler no matter what language you speak.
Thanks,
Qu
>
> "If one is less than or equal to i and i is less than or equal to
> four."
>
> Or
>
> "If i is greater than or equal to one and i is less than or equal to
> four."
>
> ?
>
> I read it the second way, and I believe most English speakers read it
> that way too.
>
> It took me a minute or two to understand the original method, because
> my mind likes to take a variable and keep it on the same side of the
> comparison, and the variable should always be first.
>
> -- Steve
>
>
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next prev parent reply other threads:[~2019-10-21 14:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 9:47 [PATCH v3] tools/lib/traceevent, perf tools: Handle %pU format correctly Qu Wenruo
2019-10-21 13:56 ` Steven Rostedt
2019-10-21 14:03 ` Qu Wenruo
2019-10-21 14:24 ` Steven Rostedt
2019-10-21 14:30 ` Qu Wenruo [this message]
2019-10-21 15:34 ` Steven Rostedt
2019-10-29 14:39 ` [tools/lib/traceevent, perf tools] b28d7df1d3: stderr.In_file_included_from_event-parse.c kernel test robot
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