BUG/MEDIUM: config: fix cpu-map notation with both process and threads
The application of a cpu-map statement with both process and threads
is broken (P-Q/1 or 1/P-Q notation).
For example, before the fix, when using P-Q/1, proc_t1 would be updated.
Then it would be AND'ed with thread which is still 0 and thus does
nothing.
Another problem is when using 1/1[-Q], thread[0] is defined. But if
there is multiple processes, every processes will use this define
affinity even if it should be applied only to 1st process.
The solution to the fix is a little bit too complex for my taste and
there is maybe a simpler solution but I did not wish to break the
storage of global.cpu_map, as it is quite painful to test all the
use-cases. Besides, this code will probably be clean up when
multiprocess support removed on the future version.
Let's try to explain my logic.
* either haproxy runs in multiprocess or multithread mode. If on
multiprocess, we should consider proc_t1 (P-Q/1 notation). If on
multithread, we should consider thread (1/P-Q notation). However
during parsing, the final number of processes or threads is unknown,
thus we have to consider the two possibilities.
* there is a special case for the first thread / first process which is
present in both execution modes. And as a matter of fact cpu-map 1 or
1/1 notation represents the same thing. Thus, thread[0] and proc_t1[0]
represents the same thing. To solve this problem, only thread[0] is
used for this special case.
This fix must be backported up to 2.0.
(cherry picked from commit af02c574064873cac3fb10993293d34a4eb94d2f)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/cfgparse-global.c b/src/cfgparse-global.c
index ca447bb..80b7391 100644
--- a/src/cfgparse-global.c
+++ b/src/cfgparse-global.c
@@ -1078,22 +1078,34 @@
}
}
} else {
- /* Mapping at the thread level. All threads are retained
- * for process 1, and only thread 1 is retained for other
- * processes.
+ /* Mapping at the thread level.
+ * Either proc and/or thread must be 1 and only 1. All
+ * other combinations are silently ignored.
*/
if (thread == 0x1) {
+ int val;
+
/* first thread, iterate on processes. E.g. cpu-map 1-4/1 0-3 */
for (i = n = 0; i < MAX_PROCS; i++) {
/* No mapping for this process */
if (!(proc & (1UL << i)))
continue;
- if (!autoinc)
- global.cpu_map.proc_t1[i] = cpus;
+
+ if (!autoinc) {
+ val = cpus;
+ }
else {
n += my_ffsl(cpus >> n);
- global.cpu_map.proc_t1[i] = (1UL << (n-1));
+ val = 1UL << (n - 1);
}
+
+ /* For first process, thread[0] is used.
+ * Use proc_t1[N] for all others
+ */
+ if (!i)
+ global.cpu_map.thread[0] = val;
+ else
+ global.cpu_map.proc_t1[i] = val;
}
}
diff --git a/src/haproxy.c b/src/haproxy.c
index f55a97b..2163326 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -3680,8 +3680,11 @@
#ifdef USE_CPU_AFFINITY
/* Now the CPU affinity for all threads */
- if (global.cpu_map.proc_t1[relative_pid-1])
- global.cpu_map.thread[0] &= global.cpu_map.proc_t1[relative_pid-1];
+
+ /* If on multiprocess, use proc_t1 except for the first process.
+ */
+ if ((relative_pid - 1) > 0)
+ global.cpu_map.thread[0] = global.cpu_map.proc_t1[relative_pid-1];
for (i = 0; i < global.nbthread; i++) {
if (global.cpu_map.proc[relative_pid-1])