From: Stelian Pop <stelian@popies.net>
Date: Fri, 10 Jun 2011 12:41:53 +0000 (+0000)
Subject: Improve data throughput in dump by allowing the slaves to compress in parallel
X-Git-Url: https://git.wh0rd.org/?a=commitdiff_plain;h=bfff36e172f87dd9f159121ee48b995da4905ea6;p=dump.git
Improve data throughput in dump by allowing the slaves to compress in parallel
---
diff --git a/CHANGES b/CHANGES
index 0000bb1..8796462 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,11 @@
-$Id: CHANGES,v 1.327 2011/06/10 12:17:23 stelian Exp $
+$Id: CHANGES,v 1.328 2011/06/10 12:41:53 stelian Exp $
+
+Changes between versions 0.4b44 and 0.4b45 (released ?????????????)
+===================================================================
+
+1. Improve data throughput when using compression in dump by
+ allowing multiple slaves to compress in parallel. Thanks
+ to Phillip Susi <psusi@cfl.rr.com> for the patch.
Changes between versions 0.4b43 and 0.4b44 (released June 10, 2011)
===================================================================
diff --git a/dump/tape.c b/dump/tape.c
index e46d626..ec1b311 100644
--- a/dump/tape.c
+++ b/dump/tape.c
@@ -37,7 +37,7 @@
#ifndef lint
static const char rcsid[] =
- "$Id: tape.c,v 1.93 2011/05/20 09:52:19 stelian Exp $";
+ "$Id: tape.c,v 1.94 2011/06/10 12:41:54 stelian Exp $";
#endif /* not lint */
#include <config.h>
@@ -178,10 +178,15 @@ static int tapea_volume; /* value of spcl.c_tapea at volume start */
int master; /* pid of master, for sending error signals */
int tenths; /* length of tape overhead per block written */
-static int caught; /* have we caught the signal to proceed? */
-static int ready; /* have we reached the lock point without having */
+static int caught1; /* have we caught the signal to proceed? */
+static int ready1; /* have we reached the lock point without having */
/* received the SIGUSR2 signal from the prev slave? */
-static sigjmp_buf jmpbuf; /* where to jump to if we are ready when the */
+static sigjmp_buf jmpbuf1; /* where to jump to if we are ready when the */
+ /* SIGUSR1 arrives from the previous slave */
+static int caught2; /* have we caught the signal to proceed? */
+static int ready2; /* have we reached the lock point without having */
+ /* received the SIGUSR2 signal from the prev slave? */
+static sigjmp_buf jmpbuf2; /* where to jump to if we are ready when the */
/* SIGUSR2 arrives from the previous slave */
#ifdef USE_QFA
static int gtperr = 0;
@@ -1028,15 +1033,26 @@ Exit(int status)
exit(status);
}
+/*
+ * proceed - handler for SIGUSR1, used to synchronize IO between the slaves.
+ */
+static void
+proceed1(UNUSED(int signo))
+{
+ if (ready1)
+ siglongjmp(jmpbuf1, 1);
+ caught1++;
+}
+
/*
* proceed - handler for SIGUSR2, used to synchronize IO between the slaves.
*/
static void
-proceed(UNUSED(int signo))
+proceed2(UNUSED(int signo))
{
- if (ready)
- siglongjmp(jmpbuf, 1);
- caught++;
+ if (ready2)
+ siglongjmp(jmpbuf2, 1);
+ caught2++;
}
void
@@ -1058,16 +1074,21 @@ enslave(void)
sigaction(SIGTERM, &sa, NULL); /* Slave sends SIGTERM on dumpabort() */
sa.sa_handler = sigpipe;
sigaction(SIGPIPE, &sa, NULL);
- sa.sa_handler = proceed;
+ sa.sa_handler = proceed1;
+ sa.sa_flags = SA_RESTART;
+ sigaction(SIGUSR1, &sa, NULL); /* Slave sends SIGUSR1 to next slave */
+ sa.sa_handler = proceed2;
sa.sa_flags = SA_RESTART;
sigaction(SIGUSR2, &sa, NULL); /* Slave sends SIGUSR2 to next slave */
}
for (i = 0; i < SLAVES; i++) {
if (i == slp - &slaves[0]) {
- caught = 1;
+ caught1 = 1;
+ caught2 = 1;
} else {
- caught = 0;
+ caught1 = 0;
+ caught2 = 0;
}
if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
@@ -1140,7 +1161,9 @@ killall(void)
* previous process before writing to the tape, and sends SIGUSR2
* to the next process when the tape write completes. On tape errors
* a SIGUSR1 is sent to the master which then terminates all of the
- * slaves.
+ * slaves. Each process sends SIGUSR1 to the next to signal that it
+ * is time to start reading from the disk, after it finishes reading
+ * and moves to the compression phase.
*/
static void
doslave(int cmd,
@@ -1177,6 +1200,7 @@ doslave(int cmd,
sigset_t set;
sigemptyset(&set);
+ sigaddset(&set, SIGUSR1);
sigaddset(&set, SIGUSR2);
sigprocmask(SIG_BLOCK, &set, NULL);
sigemptyset(&set);
@@ -1240,6 +1264,15 @@ doslave(int cmd,
while ((nread = dump_atomic_read( cmd, (char *)slp->req, reqsiz)) == reqsiz) {
struct req *p = slp->req;
+ /* wait for previous slave to finish reading */
+ if (sigsetjmp(jmpbuf1, 1) == 0) {
+ ready1 = 1;
+ if (!caught1)
+ sigsuspend(&set);
+ }
+ ready1 = 0;
+ caught1 = 0;
+
for (trecno = 0; trecno < ntrec;
trecno += p->count, p += p->count) {
if (p->dblk) { /* read a disk block */
@@ -1252,6 +1285,8 @@ doslave(int cmd,
quit("master/slave protocol botched.\n");
}
}
+ /* signal next slave to start reading */
+ (void) kill(nextslave, SIGUSR1);
/* Try to write the data... */
wrote = 0;
@@ -1345,13 +1380,13 @@ doslave(int cmd,
do_compress = compressed;
#endif /* HAVE_ZLIB || HAVE_BZLIB || HAVE_LZO */
- if (sigsetjmp(jmpbuf, 1) == 0) {
- ready = 1;
- if (!caught)
+ if (sigsetjmp(jmpbuf2, 1) == 0) {
+ ready2 = 1;
+ if (!caught2)
sigsuspend(&set);
}
- ready = 0;
- caught = 0;
+ ready2 = 0;
+ caught2 = 0;
#ifdef USE_QFA
if (gTapeposfd >= 0) {