On Mon, 11 Oct 2021 09:30:57 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote: > Hello Andrew, > > > Thank you for great questions! > > On Sun, 10 Oct 2021 15:01:40 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > On Fri, 8 Oct 2021 09:45:06 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote: > > > > > The user space can get the monitoring results via the 'damon_aggregated' > > > tracepoint event. For simplicity and brevity, the tracepoint events > > > have some duplicated information such as 'target_id' and 'nr_regions', > > > though. As a result, its size is greater than really needed. Also, > > > dealing with the tracepoint could be complex for some simple use cases. > > > To provide a way for getting more efficient and simple monitoring > > > results to user space, this commit implements 'recording' feature in > > > 'damon-dbgfs'. > > > > > > The feature is exported to the user space via a new debugfs file named > > > 'record', which is located in '<debugfs>/damon/' directory. The file > > > allows users to record monitored access patterns in a regular binary > > > file in a simple format. > > > > Binary files are troublesome. > > > > Is the format of this file documented anywhere? > > No. I intended the Python script in the following patch[1] and the user space > tool[2] to be used as such documents. I will write up one before the next > spin. > > [1] https://lore.kernel.org/linux-mm/20211008094509.16179-3-sj@xxxxxxxxxx/ > [2] https://github.com/awslabs/damo/blob/v0.0.5/_damon_result.py#L38 > > > > > I assume that the file's contents will have different representations > > depending on host endianness and word size and I further assume that > > the provided python script won't handle this very well? > > You're right. I will make the script properly handle the cases in the next > spin. Well, rather than messing with the different file formats, you could make the binary file machine-independent. Decide on the endianness and word size, implement them and document them. Things like cpu_to_le32 are zero-cost on little-endian machines.
