From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sai Prakash Ranjan Subject: Re: [PATCH 2/6] pstore: Add event tracing support Date: Wed, 26 Sep 2018 15:22:59 +0530 Message-ID: <67f42dd8-31e3-99fa-06b7-bd9f860ccef8@codeaurora.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Joel Fernandes Cc: Tom Zanussi , Catalin Marinas , Will Deacon , Vivek Gautam , Joel Fernandes , Prasad Sodagudi , Ingo Molnar , tsoni@codeaurora.org, Anton Vorontsov , Ingo Molnar , Sibi Sankar , Laura Abbott , kernel-team , devicetree@vger.kernel.org, Kees Cook , Arnd Bergmann , linux-arm-msm@vger.kernel.org, Steven Rostedt , Jason Baron , Rob Herring , Tingwei Zhang List-Id: devicetree@vger.kernel.org On 9/26/2018 2:10 AM, Joel Fernandes wrote: > On Tue, Sep 25, 2018 at 1:39 PM, Joel Fernandes wrote: >> On Tue, Sep 25, 2018 at 1:37 PM, Joel Fernandes wrote: >>> On Sun, Sep 23, 2018 at 8:33 AM, Sai Prakash Ranjan >>> wrote: >>>> On 9/22/2018 10:07 PM, Sai Prakash Ranjan wrote: >>>>> >>>>> On 9/22/2018 2:35 PM, Joel Fernandes wrote: >>>>>> >>>>>> On Sat, Sep 8, 2018 at 4:28 PM Sai Prakash Ranjan >>>>>> wrote: >>>>>>> >>>>>>> >>>>>>> + >>>>>>> + trace_seq_init(&iter->seq); >>>>>>> + iter->ent = fbuffer->entry; >>>>>>> + event_call->event.funcs->trace(iter, 0, event); >>>>>>> + trace_seq_putc(&iter->seq, 0); >>>>>> >>>>>> >>>>>> Would it be possible to store the binary trace record in the pstore >>>>>> buffer instead of outputting text? I suspect that will both be faster >>>>>> and less space. >>>>>> >>>>> >>>>> I will try this and come back. >>>>> >>>> >>>> Hi Joel, >>>> >>>> I removed trace_seq_putc and there is some improvement seen: 203 MB/s >>>> >>>> # dd if=/dev/zero of=/dev/null status=progress >>>> 12207371264 bytes (12 GB, 11 GiB) copied, 60 s, 203 MB/s^C >>>> 24171926+0 records in >>>> 24171926+0 records out >>>> 12376026112 bytes (12 GB, 12 GiB) copied, 60.8282 s, 203 MB/s >>>> >>>> This seems good when compared to 190 MB/s seen previously. >>>> If this is Ok, then I will spin v2 with changes suggested. >>> >>> Sorry for slow reply, yes that sounds good and a worthwhile perf improvement. >>> >> >> Well so I think you should still not use spinlock to synchronize and >> split the buffer. You could expand pstore_record to have a ts field or >> introduce a new API like ->write_percpu instead of write, or >> something. But I strongly feel you should lock. For ftrace function > > Aargh, I meant you should *not* lock :-) > OK I can try this and will measure some perf difference. BTW I guess you missed my previous comment about not able to combine logs based on timestamp? Anyways I think if I add some extra ts field, then should be able to do it. Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation