Messages in this thread | | | From | Miles Bader <> | Subject | Re: tools/perf: "perf record" restricted to root in latest kernel? | Date | Thu, 07 Jan 2010 11:49:34 +0900 |
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Arnaldo Carvalho de Melo <acme@infradead.org> writes: >> Next I updated to the latest linus tree (c5974b835a), and recompiled perf. >> It still seems to work, and has obviously had a lot of features added, but >> now it only wants to let me run "perf record" if I'm root. > > Don't recall noticing such problem, here it works just fine: > > [acme@doppio linux-2.6-tip]$ mkdir tmp > [acme@doppio linux-2.6-tip]$ cd tmp > [acme@doppio tmp]$ time perf record find ~/git/ > /dev/null > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.053 MB perf.data (~2312 samples) ]
Weird... if I try your recipe, I get:
$ cd /usr/local/tmp $ ls gstlfilt.zip q2.jpg q3.jpg $ time perf record find /usr/local/src/git/ > /dev/null Fatal: Permission error - are you root?
real 0m0.032s user 0m0.004s sys 0m0.012s
> [acme@doppio linux-2.6-tip]$ uname -r > 2.6.33-rc3-tip+
Perhaps the newer version of perf works better with newer kernels, or with some specific option enabled? [Since it's a fairly new tool, I suppose it may not work well unless the perf version and the kernel version are in sync.]
I'm using a standard debian kernel:
$ uname -r 2.6.32-trunk-amd64
$ grep PERF_ /boot/config-2.6.32-trunk-amd64 CONFIG_HAVE_PERF_EVENTS=y CONFIG_PERF_EVENTS=y # CONFIG_PERF_COUNTERS is not set # CONFIG_DEBUG_PERF_USE_VMALLOC is not set
I notice that the system call which results in an error for me changed between the two versions of perf -- from "sys_perf_counter_open" to "sys_perf_event_open" -- though I don't understand the difference.
Thanks,
-Miles
-- Youth, n. The Period of Possibility, when Archimedes finds a fulcrum, Cassandra has a following and seven cities compete for the honor of endowing a living Homer.
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