From: Rob Gardner <rob.gardner@hp.com>
To: xen-devel <xen-devel@lists.xensource.com>
Subject: [PATCH] xentrace: new trace event to track lost trace records
Date: Thu, 06 Jul 2006 17:35:00 -0600 [thread overview]
Message-ID: <44AD9E24.9050808@hp.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 2042 bytes --]
Simple addition to trace.c to count trace records that are generated
when the trace buffers are full. When there is space available again, a
new record is generated that indicates how many trace records have been
thrown away. I'm working on the corresponding userland code to do
something useful with this information, and will send out an additional
patch 'soon.'
Rob Gardner
# HG changeset patch
# User rob.gardner@hp.com
# Node ID 81e7d6e0f9109bf493b7c8281ffc79d10f4dd2ab
# Parent 67f658b84025efeb2a570d2937ebc8f5e35056f7
New trace event is introduced to track lost trace records.
diff -r 67f658b84025 -r 81e7d6e0f910 xen/common/trace.c
--- a/xen/common/trace.c Thu Jul 6 18:08:37 2006
+++ b/xen/common/trace.c Thu Jul 6 23:29:26 2006
@@ -234,7 +234,8 @@
struct t_buf *buf;
struct t_rec *rec;
unsigned long flags;
-
+ static long lost_records = 0;
+
BUG_ON(!tb_init_done);
if ( (tb_event_mask & event) == 0 )
@@ -261,8 +262,24 @@
if ( (buf->prod - buf->cons) >= nr_recs )
{
+ lost_records++;
local_irq_restore(flags);
return;
+ }
+
+ if (lost_records) {
+ rec = &t_recs[smp_processor_id()][buf->prod % nr_recs];
+ rec->cycles = (u64)get_cycles();
+ rec->event = TRC_LOST_RECORDS;
+ rec->data[0] = lost_records;
+ rec->data[1] = 0;
+ rec->data[2] = 0;
+ rec->data[3] = 0;
+ rec->data[4] = 0;
+
+ wmb();
+ buf->prod++;
+ lost_records = 0;
}
rec = &t_recs[smp_processor_id()][buf->prod % nr_recs];
diff -r 67f658b84025 -r 81e7d6e0f910 xen/include/public/trace.h
--- a/xen/include/public/trace.h Thu Jul 6 18:08:37 2006
+++ b/xen/include/public/trace.h Thu Jul 6 23:29:26 2006
@@ -26,6 +26,7 @@
#define TRC_VMXIO 0x00088000 /* VMX io emulation trace */
/* Trace events per class */
+#define TRC_LOST_RECORDS (TRC_GEN + 1)
#define TRC_SCHED_DOM_ADD (TRC_SCHED + 1)
#define TRC_SCHED_DOM_REM (TRC_SCHED + 2)
[-- Attachment #2: trace-patch --]
[-- Type: text/plain, Size: 1647 bytes --]
# HG changeset patch
# User rob.gardner@hp.com
# Node ID 81e7d6e0f9109bf493b7c8281ffc79d10f4dd2ab
# Parent 67f658b84025efeb2a570d2937ebc8f5e35056f7
New trace event is introduced to track lost trace records.
diff -r 67f658b84025 -r 81e7d6e0f910 xen/common/trace.c
--- a/xen/common/trace.c Thu Jul 6 18:08:37 2006
+++ b/xen/common/trace.c Thu Jul 6 23:29:26 2006
@@ -234,7 +234,8 @@
struct t_buf *buf;
struct t_rec *rec;
unsigned long flags;
-
+ static long lost_records = 0;
+
BUG_ON(!tb_init_done);
if ( (tb_event_mask & event) == 0 )
@@ -261,8 +262,24 @@
if ( (buf->prod - buf->cons) >= nr_recs )
{
+ lost_records++;
local_irq_restore(flags);
return;
+ }
+
+ if (lost_records) {
+ rec = &t_recs[smp_processor_id()][buf->prod % nr_recs];
+ rec->cycles = (u64)get_cycles();
+ rec->event = TRC_LOST_RECORDS;
+ rec->data[0] = lost_records;
+ rec->data[1] = 0;
+ rec->data[2] = 0;
+ rec->data[3] = 0;
+ rec->data[4] = 0;
+
+ wmb();
+ buf->prod++;
+ lost_records = 0;
}
rec = &t_recs[smp_processor_id()][buf->prod % nr_recs];
diff -r 67f658b84025 -r 81e7d6e0f910 xen/include/public/trace.h
--- a/xen/include/public/trace.h Thu Jul 6 18:08:37 2006
+++ b/xen/include/public/trace.h Thu Jul 6 23:29:26 2006
@@ -26,6 +26,7 @@
#define TRC_VMXIO 0x00088000 /* VMX io emulation trace */
/* Trace events per class */
+#define TRC_LOST_RECORDS (TRC_GEN + 1)
#define TRC_SCHED_DOM_ADD (TRC_SCHED + 1)
#define TRC_SCHED_DOM_REM (TRC_SCHED + 2)
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next reply other threads:[~2006-07-06 23:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-06 23:35 Rob Gardner [this message]
2006-08-18 13:20 ` [PATCH] xentrace: new trace event to track lost trace records Mark Williamson
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