@@ -205,8 +205,8 @@ static void test_config_functions(void)
orig_cfg.buckets[THROTTLE_OPS_READ].avg = 69;
orig_cfg.buckets[THROTTLE_OPS_WRITE].avg = 23;
- orig_cfg.buckets[THROTTLE_BPS_TOTAL].max = 0; /* should be corrected */
- orig_cfg.buckets[THROTTLE_BPS_READ].max = 1; /* should not be corrected */
+ orig_cfg.buckets[THROTTLE_BPS_TOTAL].max = 0;
+ orig_cfg.buckets[THROTTLE_BPS_READ].max = 1;
orig_cfg.buckets[THROTTLE_BPS_WRITE].max = 120;
orig_cfg.buckets[THROTTLE_OPS_TOTAL].max = 150;
@@ -246,8 +246,8 @@ static void test_config_functions(void)
g_assert(final_cfg.buckets[THROTTLE_OPS_READ].avg == 69);
g_assert(final_cfg.buckets[THROTTLE_OPS_WRITE].avg == 23);
- g_assert(final_cfg.buckets[THROTTLE_BPS_TOTAL].max == 15.3);/* fixed */
- g_assert(final_cfg.buckets[THROTTLE_BPS_READ].max == 1); /* not fixed */
+ g_assert(final_cfg.buckets[THROTTLE_BPS_TOTAL].max == 0);
+ g_assert(final_cfg.buckets[THROTTLE_BPS_READ].max == 1);
g_assert(final_cfg.buckets[THROTTLE_BPS_WRITE].max == 120);
g_assert(final_cfg.buckets[THROTTLE_OPS_TOTAL].max == 150);
@@ -380,6 +380,16 @@ static void throttle_fix_bucket(LeakyBucket *bkt)
}
}
+/* undo internal bucket parameter changes (see throttle_fix_bucket()) */
+static void throttle_unfix_bucket(LeakyBucket *bkt)
+{
+ double min = bkt->avg / 10;
+
+ if (bkt->max == min) {
+ bkt->max = 0;
+ }
+}
+
/* take care of canceling a timer */
static void throttle_cancel_timer(QEMUTimer *timer)
{
@@ -420,7 +430,13 @@ void throttle_config(ThrottleState *ts,
*/
void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg)
{
+ int i;
+
*cfg = ts->cfg;
+
+ for (i = 0; i < BUCKETS_COUNT; i++) {
+ throttle_unfix_bucket(&cfg->buckets[i]);
+ }
}
Throttling has a weird property that throttle_get_config() does not always return the same throttling settings that were given with throttle_config(). In other words, the set and get functions aren't symmetric. If .max is 0 then the throttling code assigns a default value of .avg / 10 in throttle_config(). This is an implementation detail of the throttling algorithm. When throttle_get_config() is called the .max value returned should still be 0. Users are exposed to this quirk via "info block" or "query-block" monitor commands. This has caused confusion because it looks like a bug when an unexpected value is reported. This patch hides the .max value adjustment in throttle_get_config() and updates test-throttle.c appropriately. Reported-by: Nini Gu <ngu@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- tests/test-throttle.c | 8 ++++---- util/throttle.c | 16 ++++++++++++++++ 2 files changed, 20 insertions(+), 4 deletions(-)