[zeromq-dev] [Openpgm-dev] latency increasing

Pavol Malosek malosek at fastmq.com
Thu Feb 12 17:21:29 CET 2009

----- Original Message ----- 
From: "Steven McCoy" <steven.mccoy at miru.hk>
Sent: Friday, February 06, 2009 9:13 AM

> This all happens if the SPM heartbeat intervals are too low.

Hello Steven,

I did not have luck with tunning spm_heartbeat intervals, throughput has 
been still around 4Mb/s for 1450B messages.
By the measurements we have found that g_trash_stack_height () function call 
in pgm_txw_alloc () takes singificant amount of time (especially for high 
data rates and longer reliability intervals) - quick look into docs showed 
that g_trash_stack_height() has O(n) complexity:(

What do you think about patch like:

--- include/pgm/txwi.h  (revision 322)
+++ include/pgm/txwi.h  (working copy)
@@ -98,7 +98,7 @@
 static inline gpointer pgm_txw_alloc (pgm_txw_t* t)
     gpointer p;
-    if (g_trash_stack_height(&t->trash_data)) {
+    if (t->trash_data) {
        p = g_trash_stack_pop (&t->trash_data);
     } else {
        p = g_slice_alloc (t->max_tpdu);

With this patch we are able to reach 100Mb rate limit.


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