From: David Ahern <dsahern@gmail.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Perf Users <linux-perf-users@vger.kernel.org>,
kernel-team@lge.com
Subject: Re: perf probe and bitfields
Date: Fri, 26 Jan 2018 09:28:49 -0700 [thread overview]
Message-ID: <b506165b-22bf-db70-0ef5-30c4ee4e2295@gmail.com> (raw)
In-Reply-To: <20180126065656.GD22737@sejong>
On 1/25/18 11:56 PM, Namhyung Kim wrote:
> Hi David,
>
> On Fri, Jan 19, 2018 at 08:43:50AM -0800, David Ahern wrote:
>> Hi Arnaldo / Masami:
>>
>> Are there known issues / limitations with perf probe and bitfields?
>>
>> Here's an example: pkt_type is a bitfield in sk_buff. When I put a probe
>> in arp_rcv to examine the pkt_type value:
>>
>> $ perf probe 'arp_rcv ptype=skb->pkt_type dev=dev->name:string'
>
> Bitfield type takes 3 parameters according to the Doc/perf-probe.txt.
> Maybe it's like 'ptype=skb->pkt_type:b3@0/8' ?
missed that. Thanks, Namyhung.
next prev parent reply other threads:[~2018-01-26 16:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 16:43 perf probe and bitfields David Ahern
2018-01-26 6:56 ` Namhyung Kim
2018-01-26 16:28 ` David Ahern [this message]
2018-01-27 5:04 ` Masami Hiramatsu
2018-01-30 16:53 ` David Ahern
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