Dear Upakul,
if it is not too much of a bother, can you please check if the attached
patch fixes the CPU usage problem?
It is a port of Ingo Molnar's CPU usage fix - we have used that patch in
iperf with great benefit (the CPU usage went down to very modest values).
Regards
Gerrit
Quoting Upakul Barkakaty:
| Hi Jon,
|
| I have upgraded to Iperf-v2.0.4. But unfortunately, even with this version
| I observed that the Iperf client was consuming all the CPU MIPS even if it
| was running at 1 Mbps.
|
| --
| Regards,
| Upakul Barkakaty
|
| On 4/23/08, Jon Dugan <[EMAIL PROTECTED]> wrote:
|
| Upakul,
|
| Which version of Iperf are you using? This should be resolved in Iperf
| MailScanner warning: numerical links are often malicious: 2.0.4.
|
| Jon
|
| Upakul Barkakaty wrote:
|
| Hi all,
|
| I was using the Iperf UDP client to test the network bandwidth and CPU
| Utilization. I observed that the Iperf client was consuming all the
| CPU MIPS even if it was running at 1 Mbps.
|
| On investigation, It looks like the delay_loop() function in the file
| Client.cpp is blocking in the kernel space while adjusting the
| thoughput speeds. On trying out replacing delay_loop() by usleep()
| function, Idle MIPS were available.
|
| Please can you let me know if this is an intended behaviour keeping in
| mind some particular purpose?
|
The University of Aberdeen is a charity registered in Scotland, No SC013683.
[Thread]: Replace thread_rest() with condition variables
This applies the patch by Ingo Molnar from
http://marc.info/?l=linux-kernel&m=119088670113210&w=2
by reverting previous changes that coincided with changes made by this
patch. Other than that, the patch is the original from the above URL.
Gerrit
---
compat/Thread.c | 6 ------
src/Reporter.c | 37 +++++++++----------------------------
src/main.cpp | 2 ++
3 files changed, 11 insertions(+), 34 deletions(-)
--- a/compat/Thread.c
+++ b/compat/Thread.c
@@ -405,12 +405,6 @@ int thread_numuserthreads( void ) {
void thread_rest ( void ) {
#if defined( HAVE_THREAD )
#if defined( HAVE_POSIX_THREAD )
-#if defined( _POSIX_PRIORITY_SCHEDULING )
- sched_yield();
-#else
- usleep( 0 );
-#endif
-
#else // Win32
SwitchToThread( );
#endif
--- a/src/Reporter.c
+++ b/src/Reporter.c
@@ -110,9 +110,8 @@ report_statistics multiple_reports[kRepo
char buffer[64]; // Buffer for printing
ReportHeader *ReportRoot = NULL;
-int threadWait = 0;
-int threadSleeping = 0;
extern Condition ReportCond;
+extern Condition ReportDoneCond;
int reporter_process_report ( ReportHeader *report );
void process_report ( ReportHeader *report );
int reporter_handle_packet( ReportHeader *report );
@@ -340,7 +339,7 @@ void ReportPacket( ReportHeader* agent,
// item
while ( index == 0 ) {
Condition_Signal( &ReportCond );
- thread_rest();
+ Condition_Wait( &ReportDoneCond );
index = agent->reporterindex;
}
agent->agentindex = 0;
@@ -348,11 +347,9 @@ void ReportPacket( ReportHeader* agent,
// Need to make sure that reporter is not about to be "lapped"
while ( index - 1 == agent->agentindex ) {
Condition_Signal( &ReportCond );
- thread_rest();
+ Condition_Wait( &ReportDoneCond );
index = agent->reporterindex;
}
- if (threadSleeping)
- Condition_Signal( &ReportCond );
// Put the information there
memcpy( agent->data + agent->agentindex, packet, sizeof(ReportStruct) );
@@ -382,9 +379,6 @@ void CloseReport( ReportHeader *agent, R
packet->packetLen = 0;
ReportPacket( agent, packet );
packet->packetID = agent->report.cntDatagrams;
- if (threadSleeping)
- Condition_Signal( &ReportCond );
-
}
}
@@ -396,9 +390,6 @@ void CloseReport( ReportHeader *agent, R
void EndReport( ReportHeader *agent ) {
if ( agent != NULL ) {
int index = agent->reporterindex;
- if (threadSleeping)
- Condition_Signal( &ReportCond );
-
while ( index != -1 ) {
thread_rest();
index = agent->reporterindex;
@@ -467,10 +458,6 @@ void ReportSettings( thread_Settings *ag
* Update the ReportRoot to include this report.
*/
Condition_Lock( ReportCond );
- if ( isUDP(agent) )
- threadWait = 0;
- else
- threadWait = 1;
reporthdr->next = ReportRoot;
ReportRoot = reporthdr;
Condition_Signal( &ReportCond );
@@ -567,6 +554,7 @@ void reporter_spawn( thread_Settings *th
}
Condition_Unlock ( ReportCond );
+again:
if ( ReportRoot != NULL ) {
ReportHeader *temp = ReportRoot;
//Condition_Unlock ( ReportCond );
@@ -589,19 +577,12 @@ void reporter_spawn( thread_Settings *th
// finished with report so free it
free( temp );
Condition_Unlock ( ReportCond );
+ Condition_Signal( &ReportDoneCond );
+ if (ReportRoot)
+ goto again;
}
- // yield control of CPU is another thread is waiting
- // sleep on a condition variable, as it is much cheaper
- // on most platforms than issuing schedyield or usleep
- // syscalls
- Condition_Lock ( ReportCond );
- if ( threadWait && ReportRoot != NULL) {
- threadSleeping = 1;
- Condition_TimedWait (& ReportCond, 1 );
- threadSleeping = 0;
- }
- Condition_Unlock ( ReportCond );
-
+ Condition_Signal( &ReportDoneCond );
+ usleep(10000);
} else {
//Condition_Unlock ( ReportCond );
}
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -96,6 +96,7 @@ extern "C" {
// records being accessed in a report and also to
// serialize modification of the report list
Condition ReportCond;
+ Condition ReportDoneCond;
}
// global variables only accessed within this file
@@ -142,6 +143,7 @@ int main( int argc, char **argv ) {
// Initialize global mutexes and conditions
Condition_Initialize ( &ReportCond );
+ Condition_Initialize ( &ReportDoneCond );
Mutex_Initialize( &groupCond );
Mutex_Initialize( &clients_mutex );
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