Hi, Thanks for the quick response.
> add a -v and see if more info comes out. > > perf script can be used to dump events. I tried again with -v on record, but I am still not getting any event samples in perf.data. Looking at an ASCII dump with report -D, I see 43 PERF_RECORD_MMAP entries, each of which appears to be related to a kernel module, but nothing for any of the events I have selected to sample (each is simply listed like "page-faults stats:"). The run ends like this every time: [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.004 MB perf.data (~194 samples) ] "Woken up 1 times" seemed suspicious, if record should be sampling at 1000Hz. I tried using -F 1000 and adding cycles to my events list both in an effort to get 1000Hz samples, but as far as I could tell, there was no change in the recorded data. Also note that when using -v with record, I get the message "failed to write feature 2" at the very end of the run output. I do not get that message without -v. I don't know what it's trying to tell me and haven't looked at the source code yet. The command I am running is a threaded python script (spawns workers). As I understand the documentation, I shouldn't need any additional flags for perf to collect data on all the threads, since it reads like counter inheritance is on by default. In other words, I believe perf record should be working in what is documented as "per-process" mode by default. I tried using -i with record in case I wasn't understanding correctly, but that didn't change anything. I will play with this more tomorrow but any further advice is appreciated. I feel like I'm probably just missing a switch or something that's not entirely obvious from the scant documentation I have found. Thanks again. Andy -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
