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authorMarkus Metzger <markus.t.metzger@intel.com>2013-04-10 13:43:41 +0200
committerMarkus Metzger <markus.t.metzger@intel.com>2014-01-16 12:58:53 +0100
commitd0fa75352b7ffd586499d28983bff5d714e5211a (patch)
tree29c8cc4dc40b9d008dcc9754c2781e11d99a9c7c /gdb
parent5de9129b066591c6ef57829ab9e1c2a030de49af (diff)
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btrace: increase buffer size
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.
Diffstat (limited to 'gdb')
-rw-r--r--gdb/ChangeLog4
-rw-r--r--gdb/common/linux-btrace.c25
2 files changed, 19 insertions, 10 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index acd6b02..50c6bcd 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,9 @@
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.
* record-btrace.c (record_btrace_info): Adjust number of calls
and insns.
diff --git a/gdb/common/linux-btrace.c b/gdb/common/linux-btrace.c
index 5474049..e469900 100644
--- a/gdb/common/linux-btrace.c
+++ b/gdb/common/linux-btrace.c
@@ -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: