Messages in this thread | | | Subject | Re: [PATCH v1 3/3] perf cs-etm: Remove callback cs_etm_find_snapshot() | From | James Clark <> | Date | Tue, 22 Jun 2021 15:29:35 +0100 |
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On 28/05/2021 17:15, Leo Yan wrote: > The callback cs_etm_find_snapshot() is invoked for snapshot mode, its > main purpose is to find the correct AUX trace data and returns "head" > and "old" (we can call "old" as "old head") to the caller, the caller > __auxtrace_mmap__read() uses these two pointers to decide the AUX trace > data size. > > cs_etm_find_snapshot() should be removed with below reasons:
Hi Leo,
I came across this other comment in coresight-tmc-etr.c that should probably be fixed up if we remove cs_etm_find_snapshot(). The same is duplicated in a few other files:
/* * In snapshot mode we simply increment the head by the number of byte * that were written. User space function cs_etm_find_snapshot() will * figure out how many bytes to get from the AUX buffer based on the * position of the head. */ if (etr_perf->snapshot) handle->head += size;
I'm still reviewing patch 1 and 2 as well.
James
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