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btrace: increase buffer size

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Try to allocate as much buffer as we can for each thread with a maximum
of 64KB.

2014-01-16  Markus Metzger  <markus.t.metzger@intel.com>

	* common/linux-btrace.c (linux_enable_btrace): Enlarge buffer.
This commit is contained in:
Markus Metzger 2013-04-10 13:43:41 +02:00
parent 5de9129b06
commit d0fa75352b
2 changed files with 19 additions and 10 deletions
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4
gdb/ChangeLog
View file

@ -1,3 +1,7 @@
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* common/linux-btrace.c (linux_enable_btrace): Enlarge buffer.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (ftrace_new_function): Start counting at one.

25
gdb/common/linux-btrace.c
View file

@ -423,7 +423,7 @@ struct btrace_target_info *
linux_enable_btrace (ptid_t ptid)
{
struct btrace_target_info *tinfo;
int pid;
int pid, pg;
tinfo = xzalloc (sizeof (*tinfo));
tinfo->ptid = ptid;
@ -451,17 +451,22 @@ linux_enable_btrace (ptid_t ptid)
if (tinfo->file < 0)
goto err;
/* We hard-code the trace buffer size.
At some later time, we should make this configurable. */
tinfo->size = 1;
tinfo->buffer = mmap (NULL, perf_event_mmap_size (tinfo),
PROT_READ, MAP_SHARED, tinfo->file, 0);
if (tinfo->buffer == MAP_FAILED)
goto err_file;
/* We try to allocate as much buffer as we can get.
We could allow the user to specify the size of the buffer, but then
we'd leave this search for the maximum buffer size to him. */
for (pg = 4; pg >= 0; --pg)
{
/* The number of pages we request needs to be a power of two. */
tinfo->size = 1 << pg;
tinfo->buffer = mmap (NULL, perf_event_mmap_size (tinfo),
PROT_READ, MAP_SHARED, tinfo->file, 0);
if (tinfo->buffer == MAP_FAILED)
continue;
return tinfo;
return tinfo;
}
err_file:
/* We were not able to allocate any buffer. */
close (tinfo->file);
err: