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Message-ID: <7d571b9d-2066-8217-5485-da0e6ace65eb@arm.com>
Date:   Mon, 28 Mar 2022 09:33:10 +0100
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Subject: Re: [PATCH v4 01/10] Use IDR to maintain all the enabled sources'
 paths.
To:     Jinlong Mao <quic_jinlmao@quicinc.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Mathieu Poirier <mathieu.poirier@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>, coresight@lists.linaro.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Tao Zhang <quic_taozha@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Hao Zhang <quic_hazha@quicinc.com>,
        linux-arm-msm@vger.kernel.org
References: <20220324121734.21531-1-quic_jinlmao@quicinc.com>
 <20220324121734.21531-2-quic_jinlmao@quicinc.com>
 <YjxjXnXAXVXfZqr/@kroah.com>
 <e78ff137-fc5e-ff00-0e57-91304288d860@quicinc.com>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
In-Reply-To: <e78ff137-fc5e-ff00-0e57-91304288d860@quicinc.com>
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On 24/03/2022 14:23, Jinlong Mao wrote:
> Hi Greg,
> 
> Thanks for your review.
> 
> On 3/24/2022 8:26 PM, Greg Kroah-Hartman wrote:
>> On Thu, Mar 24, 2022 at 08:17:25PM +0800, Mao Jinlong wrote:
>>> Use hash length of the source's device name to map to the pointer
>>> of the enabled path. Using IDR will be more efficient than using
>>> the list. And there could be other sources except STM and CPU etms
>>> in the new HWs. It is better to maintain all the paths together.
>>>
>>> Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
>>> ---
>>>   drivers/hwtracing/coresight/coresight-core.c | 75 +++++++-------------
>>>   1 file changed, 26 insertions(+), 49 deletions(-)
>> Your subject line is odd.  Please put back the driver subsystem in the
>> subject line so that it makes more sense.
> I will update the subject in next version.
>>
>> And how have you measured "more efficient"?
> 
> Using IDR would be better than doing a sequential search as there will 
> be much more device  in future.

Where do we use sequential search now ? For non-CPU bound sources, yes
we may need something. But CPU case is straight forward, and could be
retained as it is. i.e., per-cpu list of paths.

Cheers
Suzuki


> 
>>
>> thanks,
>>
>> greg k-h
> 
> Thanks
> 
> Jinlong Mao
>