Messages in this thread | | | Subject | Re: [PATCH v1 06/15] perf session: load data directory into tool process memory | From | Alexey Budankov <> | Date | Wed, 21 Oct 2020 16:01:49 +0300 |
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On 21.10.2020 13:57, Namhyung Kim wrote: > On Wed, Oct 21, 2020 at 7:25 PM Alexey Budankov > <alexey.budankov@linux.intel.com> wrote: >> >> >> On 21.10.2020 9:54, Namhyung Kim wrote: >>> Hi, >>> >>> On Tue, Oct 13, 2020 at 8:30 PM Alexey Budankov >>> <alexey.budankov@linux.intel.com> wrote: >>>> On 12.10.2020 19:49, Alexey Budankov wrote: >>>>> On 12.10.2020 19:09, Andi Kleen wrote: >>>>>> On Mon, Oct 12, 2020 at 11:58:58AM +0300, Alexey Budankov wrote: >>>>>>> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c >>>>>>> index 6afc670fdf0c..0752eec19813 100644 >>>>>>> --- a/tools/perf/util/session.c >>>>>>> +++ b/tools/perf/util/session.c >>>>>>> @@ -2212,6 +2212,17 @@ reader__process_events(struct reader *rd, struct perf_session *session, >>>>>>> goto more; >>>>>>> >>>>>>> out: >>>>>>> + if (rd->unmap_file) { >>>>>>> + int i; >>>>>>> + >>>>>>> + for (i = 0; i < NUM_MMAPS; i++) { >>>>>>> + if (mmaps[i]) { >>>>>>> + munmap(mmaps[i], mmap_size); >>>>>>> + mmaps[i] = NULL; >>>>>> >>>>>> Okay so where is the mmap? Would make more sense to put that >>>>>> into the same patch as who adds the mmap. Or is the mmap >>>>>> code already in the perf source? In that case it should >>>>>> probably be some common helper with the existing users. >>>>> >>>>> That mmap is already in the code. Agree, this part of the patch >>>>> can be applied prior the whole patch set. >>>> >>>> I take it back. Single trace file can't be unmapped yet since it also >>>> contains not only compressed records but also other records backing >>>> the data for aggregated analysis. >>> >>> Are you talking about the auxtrace? >>> >>> I thought everything will be compressed when it's enabled. >>> But if it's only for the auxtrace, maybe we can unmap them >>> with checking it as it's not the common case? >> >> I am about primary trace file. Together with PERF_RECORD_COMPRESSED >> records it contains the other records with uncompressed data (MMAP, >> FORk, COMM etc.) so it is still unsafe to unmap the trace file after >> loading. > > Oh, I think all the events coming from the kernel share the mmap > buffer so they will be compressed with SAMPLEs. Note that > synthesized events have 0 timestamp which means that they > are not queued in the ordered events and processed immediately.
Yes, they are and it will work as expected with this patch changes.
> > IIUC, here we unmap the original mmap buffer and the actual data > in MMAP/FORK/... is kept in the decomp data buffer, no?
Correct. It unmaps trace file from memory after COMPRESSED records are decompressed into separately allocated decomp objects.
Alexei
> > Thanks > Namhyung >
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