On 2021-03-31 14:35, Avri Altman wrote:
On 2021-03-31 11:34, Bart Van Assche wrote:
> On 3/30/21 8:14 PM, Can Guo wrote:
>> It works like:
>> /sys/bus/platform/drivers/ufshcd/*/monitor # echo 4096 >
>> monitor_chunk_size
>> /sys/bus/platform/drivers/ufshcd/*/monitor # echo 1 > monitor_enable
>> /sys/bus/platform/drivers/ufshcd/*/monitor # grep ^ /dev/null *
>> monitor_chunk_size:4096
>> monitor_enable:1
>> read_nr_requests:17
>> read_req_latency_avg:169
>> read_req_latency_max:594
>> read_req_latency_min:66
>> read_req_latency_sum:2887
>> read_total_busy:2639
>> read_total_sectors:136
>> write_nr_requests:116
>> write_req_latency_avg:440
>> write_req_latency_max:4921
>> write_req_latency_min:23
>> write_req_latency_sum:51052
>> write_total_busy:19584
>> write_total_sectors:928
>
> Are any of these attributes UFS-specific? If not, isn't this
> functionality that should be added to the block layer instead of to the
> UFS driver?
>
Hi Bart,
I didn't think that before because we've already have the powerful
"blktrace"
tool to collect the overall statistics of each layer.
I add this because I find it really come handy when
debug/analyze/profile
UFS driver/HW performance. And there will be UFS-specific nodes to be
added later to monitor statistics like UFS scaling, gating, doorbell,
write
booster, HPB and etc.
We are using a designated analysis tool (web-based, a lot of fancy
graphs etc.) that relies on ftrace - upiu tracer etc.
Once the raw data is there - the options/insights are endless.
Hi Avri,
Yeah, one can dig out a lot of info from ftrace/systrace raw data.
But, most important, ftrace/systrace has below disadvantages
[1] Enabling UFS/SCSI ftrace itself can impact UFS performance (a lot)
as per our profiling
[2] One needs a parser tool (only if they have one) to get the wanted
results
So we usually use ftrace to analyze some sequences, e.g., cmd-response,
suspend-resume, gating and scaling, but not quite suitable for analyzing
performance, see [1].
These nodes provide us a swift method to look into statistics during
runtime [2].
Please let me know if you have any concerns w.r.t the change.
Thanks,
Can Guo.
Thanks,
Avri
Thanks.
Can Guo.
> Thanks,
>
> Bart.
