>> --buffers-global Use shared buffer for the whole system (-k only) > > This option would be clearer as "--buffers-per-cpu" maybe ?
This makes me even more confused... The name "buffers-global" is very clear to me. Opposites would be buffers private for a CPU, for a UID, and so on. Is the option "--buffers-global" meant to be an opposite of "--buffers-uid" and "--buffers-pid"? This would seems strange since those two are only for user space tracing while "--buffers-global" is for kernel tracing. By the way, isn't "--buffers-per-cpu" default? Oh well... But the real confusion lies in the fact that I cannot see the option being used for anything. It sets the file local variable opt_buffers_global, and is used for a sanity check. But I can't see it being used for anything else. Have I missed something here? > >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> -C, --tracefile-size SIZE >> Maximum size of of each tracefile within a >> stream (in bytes). >> -W, --tracefile-count COUNT >> Used in conjunction with -C option, this >> will limit the number >> of files created to the specified count. >> >> I look in src/bin/lttng/commands/enable_channels.c, the long option >> array will point to opt_buffer_global. The only use for this file >> private variable is for a single sanity check. I cannot see any other >> use of it. Have I missed something here? >> >> But in this file, function enable_channel(), I see: >> >> dom.buf_type = LTTNG_BUFFER_GLOBAL; >> >> This is executed for the kernel case. But my buffers are still >> allocated per-cpu. What is going on? Where did this configuration go? >> What does it do? >> >> If I take this from the other end, I'd like to use the line: >> .alloc = RING_BUFFER_ALLOC_GLOBAL >> found in >> lttng-ring-buffer-metadata-client.h >> How do I make this happen? > > lttng-sessiond never creates buffers shared between CPUs for now (except > for metadata). The "--buffers-global" option is misleading and should > possibly be renamed. So it is lttng-sessiond that dictates the allocation type? I'll take a closer look at it. /Mats _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
