Messages in this thread |  | | Date | Thu, 05 Dec 2013 16:55:47 -0500 | From | Dongsheng Yang <> | Subject | Re: [PATCH 3/5] perf tools: Update the Document for perf kvm record for new behavior. |
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On 12/04/2013 09:27 AM, Arnaldo Carvalho de Melo wrote: > Em Wed, Dec 04, 2013 at 05:56:41PM -0500, Dongsheng Yang escreveu: >> As we have changed the default behavior of perf kvm to --guest enabled, >> the document about perf kvm record is outdated. This patch update it to >> show the correct output with --host/--guest/neither/both of them. > >> +++ b/tools/perf/Documentation/perf-kvm.txt >> @@ -24,10 +24,17 @@ There are a couple of variants of perf kvm: >> of an arbitrary workload. > >> 'perf kvm record <command>' to record the performance counter profile >> - of an arbitrary workload and save it into a perf data file. If both >> - --host and --guest are input, the perf data file name is perf.data.kvm. >> - If there is no --host but --guest, the file name is perf.data.guest. >> - If there is no --guest but --host, the file name is perf.data.host. >> + of an arbitrary workload and save it into a perf data file. We set the >> + default behavior of perf kvm as --guest, so if neither --host nor --guest >> + is input, the perf data file name is perf.data.guest. If --host is input, >> + the perf data file name is perf.data.kvm. If you want to record data into >> + perf.data.host, please input --host --no-guest. The behaviors are shown as >> + following: > Perhaps this is clearer: > > "Use 'perf kvm record <command>' to record the a profile of an arbitrary > workload and save it into a perf.data file. The default is to record > guest samples, use --host to ask for just host samples or both --guest > and --host for both kinds of samples to be taken." > > Argh, then I wonder why do we have --guest if the only possibility, > according to the text above, is for it to be used in the --no-guest > variant, is that the case? > > Do we really, really need to have those .host or .guest or .kvm filename > suffixes? > > Can't we have this somehow encoded in the perf.data file header and show > it when doing a report? humm, it is already, and we can see it already > in 'perf evlist': > > [root@ssdandy ~]# perf kvm record -a > ^C[ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 1.489 MB perf.data.guest (~65058 samples) ] > [root@ssdandy ~]# perf evlist > raw_syscalls:sys_enter > raw_syscalls:sys_exit > [root@ssdandy ~]# perf evlist -v > raw_syscalls:sys_enter: sample_freq=1, type: 2, config: 41, size: 96, > sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, > disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, > sample_id_all: 1, exclude_guest: 1 > raw_syscalls:sys_exit: sample_freq=1, type: 2, config: 40, size: 96, > sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, > disabled: 1, inherit: 1, enable_on_exec: 1, sample_id_all: 1, > exclude_guest: 1 > [root@ssdandy ~]# > > Humm, strange, the exclude_guest bit is set, which doesn't look like it > matches that text... > > Lemme try explicitely using --guest and --host: > > [root@ssdandy ~]# perf kvm --guest record sleep 2 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.012 MB perf.data.guest (~532 samples) ] > [root@ssdandy ~]# perf evlist -v > raw_syscalls:sys_enter: sample_freq=1, type: 2, config: 41, size: 96, sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 > raw_syscalls:sys_exit: sample_freq=1, type: 2, config: 40, size: 96, sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, disabled: 1, inherit: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 > [root@ssdandy ~]# > > exclude_guest still there... > > Then: > > [root@ssdandy ~]# perf kvm --host record sleep 2 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.012 MB perf.data.kvm (~544 samples) ] > [root@ssdandy ~]# perf evlist -v > raw_syscalls:sys_enter: sample_freq=1, type: 2, config: 41, size: 96, sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 > raw_syscalls:sys_exit: sample_freq=1, type: 2, config: 40, size: 96, sample_type: IP|TID|TIME|CALLCHAIN|ID|CPU|PERIOD|RAW, read_format: ID, disabled: 1, inherit: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 > [root@ssdandy ~]# > > Still there... oops, I've been just bitten by this odd suffixes convention, > as 'perf evlist', like all other tools, by default will look at 'perf.data', not > the 'perf kvm' convention... ... > > So again: > > [root@ssdandy ~]# perf kvm --guest record -a > ^C[ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 1.060 MB perf.data.guest (~46303 samples) ] > [root@ssdandy ~]# ls -lart perf.data* | tail -1 > -rw-------. 1 root root 1113684 Dec 4 11:11 perf.data.guest > [root@ssdandy ~]# perf evlist -v -i perf.data.guest > cycles: sample_freq=4000, size: 96, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, sample_id_all: 1, exclude_host: 1 > [root@ssdandy ~]# > > Matches the documentation, i.e. perf_event_attr.exclude_guest is not set, > meaning --guest, and .exclude_host is set, ok. > > [root@ssdandy ~]# perf kvm --host record sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.013 MB perf.data.kvm (~554 samples) ] > [root@ssdandy ~]# ls -lart perf.data* | tail -1 > -rw-------. 1 root root 15976 Dec 4 11:13 perf.data.kvm > [root@ssdandy ~]# perf evlist -v -i perf.data.kvm > cycles: sample_freq=4000, size: 96, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, sample_id_all: 1 > [root@ssdandy ~]# > > Yes, 'perf kvm record --host' actually means: "perf kvm --host --guest', as > both exclude_{host,guest} are zeroed. > > [root@ssdandy ~]# perf kvm --host --no-guest record sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.013 MB perf.data.host (~552 samples) ] > [root@ssdandy ~]# ls -lart perf.data* | tail -1 > -rw-------. 1 root root 15904 Dec 4 11:14 perf.data.host > [root@ssdandy ~]# perf evlist -v -i perf.data.host > cycles: sample_freq=4000, size: 96, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 > [root@ssdandy ~]# > > Seems all ok, just not immediately intuitive.
Okey, thanx for your verification. More detail will be added in my patches in future. > > I would expect one to do: (yeah, there was a discussion long ago, can't > remember the details right now, should have paid more attention at the > time :-\) > > perf kvm record <target> > > to mean: > > perf kvm record --host --guest <target> Do you mean we should change the default behavior of perf kvm to --host and --guest?
Hmmm, IMHO, --guest is used more frequently. > > and generate a perf.data file, just like all other tools.
Yes, just using perf.data is good to me. > What about 'perf kvm report', I think one will have to point it to the > right file to use, using -i, right?
Currently, it will check the perf_guest and perf_host to decide perf data file name if we did not use -i for it, same with perf kvm record. > So doing it at 'perf kvm record' > explicitely as well will reduce confusion and make it behave just like > all the other tools? > > Comments?
Arnaldo, I think the problem here is that do we really need the suffixes for perf kvm. Maybe your discussion long ago can make this problem more clear :).
- Yang > - Arnaldo > >> + Default('') -> perf.data.guest >> + --host -> perf.data.kvm >> + --guest -> perf.data.guest >> + --host --guest -> perf.data.kvm >> + --host --no-guest -> perf.data.host >> >> 'perf kvm report' to display the performance counter profile information >> recorded via perf kvm record. >> -- >> 1.8.2.1 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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