Messages in this thread | | | Date | Fri, 5 Jun 2015 11:06:48 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [GIT PULL 0/6] perf/core improvements and fixes |
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Em Fri, Jun 05, 2015 at 02:05:50PM +0200, Ingo Molnar escreveu: > * Wangnan (F) <wangnan0@huawei.com> wrote: <SNIP> > > One problem I can find is that, the wrapper will make perf depend on llvm. I > > don't think the compiler will be deployed in production environments... And > > also, the embedded case...
> What dependencies are there?
> On the usage side there should be very few outright dependencies: if the llvm > binary is not available, or doesn't support what you need, or there's no runtime > environment you can use to build the bytecode, you should display an informative > error message so that the user knows what is missing and how to install it.
Right, something like:
[acme@zoo ~]$ perf trace -e nanosleep usleep 1 Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit) Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug' [acme@zoo ~]$ sudo mount -o remount,mode=755 /sys/kernel/debug [sudo] password for acme: [acme@zoo ~]$ perf trace -e nanosleep usleep 1 0.565 ( 0.060 ms): usleep/17648 nanosleep(rqtp: 0x7fff22baebf0) = 0 [acme@zoo ~]$ perf trace --all-cpus Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For system wide tracing it needs to be set to -1. Hint: Try: 'sudo sh -c "echo -1 > /proc/sys/kernel/perf_event_paranoid"' Hint: The current value is 1. [acme@zoo ~]$ [acme@zoo ~]$ trace -a -e poll usleep 1 [acme@zoo ~]$ trace -a -e poll usleep 1 0.041 ( 0.000 ms): firefox/1458 ... [continued]: poll()) = 1 0.267 ( 0.003 ms): firefox/1458 poll(ufds: 0x7f43d6ea1340, nfds: 5) = 0 Timeout 0.275 ( 0.001 ms): firefox/1458 poll(ufds: 0x7f43d6ea1340, nfds: 5) = 0 Timeout 0.283 ( 0.001 ms): firefox/1458 poll(ufds: 0x7f43d6ea1340, nfds: 5) = 0 Timeout 0.979 ( 0.000 ms): gnome-terminal/2572 ... [continued]: poll()) = 1 1.056 ( 0.768 ms): firefox/1458 poll(ufds: 0x7f43d6ea1340, nfds: 5, timeout_msecs: 4294967295) ... 1.065 ( 0.009 ms): gnome-terminal/2572 poll(ufds: 0x1934250, nfds: 23, timeout_msecs: 10) = 1 1.087 ( 0.007 ms): gnome-terminal/2572 poll(ufds: 0x1934250, nfds: 23, timeout_msecs: 10) = 2 1.132 ( 0.007 ms): gnome-terminal/2572 poll(ufds: 0x1934250, nfds: 23, timeout_msecs: 10) = 1 1.161 ( 0.013 ms): gnome-terminal/2572 poll(ufds: 0x1934250, nfds: 23, timeout_msecs: 10) = 1 [acme@zoo ~]$
I.e. Explain the mistake and provide a hint to solve it, as close to the actual commands needed to perform such corrective/enabling action as possible.
- Arnaldo
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