Re: [PATCH] perf kvm record/report: 'unprocessable sample' error while recording/reporting guest data
Hi acme, I sent this patch few days ago. Unfortunately nobody has payed attention. Can you please pick this up. Regards, Ravi On Monday 07 December 2015 12:25 PM, Ravi Bangoria wrote: While recording guest samples in host using perf kvm record, it will populate unprocessable sample error, though samples will be recorded properly. While generating report using perf kvm report, no samples will be processed and same error will populate. We have seen this behaviour with upstream perf(4.4-rc3) on x86 and ppc64 hardware. Reason behind this failure is, when it tries to fetch machine from rb_tree of machines, it fails. As a part of tracing a bug, we figured out that this code was incorrectly refactored in commit 54245fdc357613633954bfd38cffb71cb9def067 ("perf session: Remove wrappers to machines__find") This patch will change the functionality such that if it can't fetch machine in first trial, it will create one node of machine and add that to rb_tree. So next time when it tries to fetch same machine from rb_tree, it won't fail. Actually it was the case before refactoring of code in aforementioned commit. This patch is generated from acme perf/core branch. Below I've mention an example that demonstrate the behaviour before and after applying patch. Before applying patch: [Note: One needs to run guest before recording data in host] ravi@ravi-bangoria:~$ ./perf kvm record -a Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? [ perf record: Captured and wrote 1.409 MB perf.data.guest (285 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 285 of event 'cycles' # Event count (approx.): 88715406 # # Overhead Command Shared Object Symbol # ... . .. # # # (For a higher level overview, try: perf report --sort comm,dso) # After applying patch: ravi@ravi-bangoria:~$ ./perf kvm record -a [ perf record: Captured and wrote 1.188 MB perf.data.guest (17 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 17 of event 'cycles' # Event count (approx.): 700746 # # Overhead Command Shared Object Symbol # ... .. # 34.19% :5758[unknown] [g] 0x818682ab 22.79% :5758[unknown] [g] 0x812dc7f8 22.79% :5758[unknown] [g] 0x818650d0 14.83% :5758[unknown] [g] 0x8161a1b6 2.49% :5758[unknown] [g] 0x818692bf 0.48% :5758[unknown] [g] 0x81869253 0.05% :5758[unknown] [g] 0x81869250 Signed-off-by: Ravi Bangoria --- tools/perf/util/session.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index c35ffdd..468de95 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -972,7 +972,7 @@ static struct machine *machines__find_for_cpumode(struct machines *machines, machine = machines__find(machines, pid); if (!machine) - machine = machines__find(machines, DEFAULT_GUEST_KERNEL_ID); + machine = machines__findnew(machines, DEFAULT_GUEST_KERNEL_ID); return machine; } -- 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/
[PATCH] perf kvm record/report: 'unprocessable sample' error while recording/reporting guest data
While recording guest samples in host using perf kvm record, it will populate unprocessable sample error, though samples will be recorded properly. While generating report using perf kvm report, no samples will be processed and same error will populate. We have seen this behaviour with upstream perf(4.4-rc3) on x86 and ppc64 hardware. Reason behind this failure is, when it tries to fetch machine from rb_tree of machines, it fails. As a part of tracing a bug, we figured out that this code was incorrectly refactored in commit 54245fdc357613633954bfd38cffb71cb9def067 ("perf session: Remove wrappers to machines__find") This patch will change the functionality such that if it can't fetch machine in first trial, it will create one node of machine and add that to rb_tree. So next time when it tries to fetch same machine from rb_tree, it won't fail. Actually it was the case before refactoring of code in aforementioned commit. This patch is generated from acme perf/core branch. Below I've mention an example that demonstrate the behaviour before and after applying patch. Before applying patch: [Note: One needs to run guest before recording data in host] ravi@ravi-bangoria:~$ ./perf kvm record -a Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? [ perf record: Captured and wrote 1.409 MB perf.data.guest (285 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 285 of event 'cycles' # Event count (approx.): 88715406 # # Overhead Command Shared Object Symbol # ... . .. # # # (For a higher level overview, try: perf report --sort comm,dso) # After applying patch: ravi@ravi-bangoria:~$ ./perf kvm record -a [ perf record: Captured and wrote 1.188 MB perf.data.guest (17 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 17 of event 'cycles' # Event count (approx.): 700746 # # Overhead Command Shared Object Symbol # ... .. # 34.19% :5758[unknown] [g] 0x818682ab 22.79% :5758[unknown] [g] 0x812dc7f8 22.79% :5758[unknown] [g] 0x818650d0 14.83% :5758[unknown] [g] 0x8161a1b6 2.49% :5758[unknown] [g] 0x818692bf 0.48% :5758[unknown] [g] 0x81869253 0.05% :5758[unknown] [g] 0x81869250 Signed-off-by: Ravi Bangoria --- tools/perf/util/session.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index c35ffdd..468de95 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -972,7 +972,7 @@ static struct machine *machines__find_for_cpumode(struct machines *machines, machine = machines__find(machines, pid); if (!machine) - machine = machines__find(machines, DEFAULT_GUEST_KERNEL_ID); + machine = machines__findnew(machines, DEFAULT_GUEST_KERNEL_ID); return machine; } -- 2.1.4 -- 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/