On 30/03/2023 00:25, Yang Shi wrote:
On Wed, Mar 29, 2023 at 9:08 AM James Clark james.clark@arm.com wrote:
On 14/03/2023 00:36, Leo Yan wrote:
On Mon, Mar 13, 2023 at 11:15:44AM -0700, Yang Shi wrote:
[...]
Just a quick summary, here we have two issues:
With command: perf record -e cs_etm/@tmc_etf63/k --kcore --per-thread \ -- taskset --cpu-list 1 uname",
perf doesn't enable "text poke" attribution.
No, it enables "text poke" and perf fails to decode coresight trace data too. It doesn't matter whether "--kcore" is after or before "-e cs/etm/@tmc_etf63/k".
Understand now. Thanks for correction, if so we can ignore this one.
Leo
To me it looks like it's only --per-thread and --kcore together that cause the issue. I can't see if that was mentioned previously in this thread.
If "--pre-thread" is not passed in, perf record failed with "failed to mmap with 12 (Cannot allocate memory)". Sorry for not mentioning this in the first place. I was quite focused on --kcore and didn't realize they may be related.
That's unrelated. That's because you have specified a sink and without --per-thread it tries to open the event on all cores. If the sink can't be reached from all cores it will fail to open. You can make it work without --per-thread if you limit it to a valid core like this, although I don't know which ones exactly would be valid for your system:
perf record -e cs_etm/@tmc_etf63/k --kcore -C 0 \ -- taskset --cpu-list 1 uname
If it is --per-thread that's causing the issue then I think I have an idea why it might be. There are some assumptions and different paths taken in decoding in that mode that aren't correct. It causes some other issues to do with ordering and timestamps as well and I wanted to fix it previously. I wouldn't say that the text-poke change has caused a regression, as decoding in this mode was always a bit buggy.
Maybe this is another reason to fix it properly.
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James Clark