r2590 - trunk/varnish-cache/bin/varnishd

[phk at projects.linpro.no]

Author: phk
Date: 2008-03-10 22:21:15 +0100 (Mon, 10 Mar 2008)
New Revision: 2590

Modified:
   trunk/varnish-cache/bin/varnishd/shmlog.c
Log:
This is slightly experimental:

Reduce SHM mutex contention further, by only holding lock over
reservation of space, and do the copying from workthread buffer
to shm buffer efter we let go of the mutex.


Modified: trunk/varnish-cache/bin/varnishd/shmlog.c
===================================================================
--- trunk/varnish-cache/bin/varnishd/shmlog.c	2008-03-10 08:22:31 UTC (rev 2589)
+++ trunk/varnish-cache/bin/varnishd/shmlog.c	2008-03-10 21:21:15 UTC (rev 2590)
@@ -185,13 +185,13 @@
 	if (loghead->ptr + l + 1 >= loghead->size)
 		vsl_wrap();
 	p = logstart + loghead->ptr;
-	memcpy(p + 1, w->wlb + 1, l - 1);
 	p[l] = SLT_ENDMARKER;
 	loghead->ptr += l;
 	assert(loghead->ptr < loghead->size);
+	UNLOCKSHM(&vsl_mtx);
+	memcpy(p + 1, w->wlb + 1, l - 1);
 	/* XXX: memory barrier here */
 	p[0] = w->wlb[0];
-	UNLOCKSHM(&vsl_mtx);
 	w->wlp = w->wlb;
 	w->wlr = 0;
 }