On 17/09/15 18:41, Mark Rutland wrote: > Hi, > > On Wed, Sep 16, 2015 at 09:54:54PM +0100, Arnaldo Carvalho de Melo wrote: >> Em Wed, Sep 16, 2015 at 06:18:49PM +0100, Mark Rutland escreveu: >>> This has been observed to result in an exit-time hang when counting >>> rare/unschedulable events with perf record, and can be triggered >>> artificially with the script below: >>> >>> ---- >>> #!/bin/sh >>> printf "REPRO: launching perf\n"; >>> ./perf record -e software/config=9/ sleep 1 & >>> PERF_PID=$!; >>> sleep 0.002; >>> kill -2 $PERF_PID; >>> printf "REPRO: waiting for perf (%d) to exit...\n" "$PERF_PID"; >>> wait $PERF_PID; >>> printf "REPRO: perf exited\n"; >>> ---- >> >> So, I run it here, without this patch, and get: >> >> [root@zoo ~]# time ./repro.sh >> REPRO: launching perf >> REPRO: waiting for perf (766) to exit... >> [ perf record: Woken up 1 times to write data ] >> [ perf record: Captured and wrote 0.015 MB perf.data ] >> REPRO: perf exited >> real 0m1.060s >> user 0m0.018s >> sys 0m0.037s > > [...] > >> What am I doing wrong? Trying to reproduce this before even looking at >> the patch :-) > > I suspect you have a shinier computer than I do! ;) >
I imagine you would also need to contrive not to write any synthesized MMAP or COMM events i.e. no access to /proc perhaps? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
