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[Qemu-devel] [PATCH] virtio-rng: Bump up quota value only when guest req
From: |
Pankaj Gupta |
Subject: |
[Qemu-devel] [PATCH] virtio-rng: Bump up quota value only when guest requests entropy |
Date: |
Fri, 10 Jul 2015 15:04:00 +0530 |
Timer was added in virtio-rng to rate limit the
entropy. It used to trigger at regular intervals to
bump up the quota value. The value of quota and timer
slice is decided based on entropy source rate in host.
This resulted in triggring of timer even when quota
is not exhausted at all and resulting in extra processing.
This patch triggers timer only when guest requests for
entropy. As soon as first request from guest for entropy
comes we set the timer. Timer bumps up the quota value
when it gets triggered.
Signed-off-by: Pankaj Gupta <address@hidden>
---
hw/virtio/virtio-rng.c | 15 ++++++++-------
include/hw/virtio/virtio-rng.h | 1 +
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
index 22b1d87..8774a0c 100644
--- a/hw/virtio/virtio-rng.c
+++ b/hw/virtio/virtio-rng.c
@@ -78,6 +78,12 @@ static void virtio_rng_process(VirtIORNG *vrng)
return;
}
+ if (vrng->activate_timer) {
+ timer_mod(vrng->rate_limit_timer,
+ qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
vrng->conf.period_ms);
+ vrng->activate_timer = false;
+ }
+
if (vrng->quota_remaining < 0) {
quota = 0;
} else {
@@ -139,8 +145,7 @@ static void check_rate_limit(void *opaque)
vrng->quota_remaining = vrng->conf.max_bytes;
virtio_rng_process(vrng);
- timer_mod(vrng->rate_limit_timer,
- qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
vrng->conf.period_ms);
+ vrng->activate_timer = true;
}
static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
@@ -196,13 +201,9 @@ static void virtio_rng_device_realize(DeviceState *dev,
Error **errp)
vrng->vq = virtio_add_queue(vdev, 8, handle_input);
vrng->quota_remaining = vrng->conf.max_bytes;
-
vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
check_rate_limit, vrng);
-
- timer_mod(vrng->rate_limit_timer,
- qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
vrng->conf.period_ms);
-
+ vrng->activate_timer = true;
register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
virtio_rng_load, vrng);
}
diff --git a/include/hw/virtio/virtio-rng.h b/include/hw/virtio/virtio-rng.h
index 0316488..3f07de7 100644
--- a/include/hw/virtio/virtio-rng.h
+++ b/include/hw/virtio/virtio-rng.h
@@ -44,6 +44,7 @@ typedef struct VirtIORNG {
*/
QEMUTimer *rate_limit_timer;
int64_t quota_remaining;
+ bool activate_timer;
} VirtIORNG;
#endif
--
1.9.3
- [Qemu-devel] [PATCH] virtio-rng: Bump up quota value only when guest requests entropy,
Pankaj Gupta <=
Re: [Qemu-devel] [PATCH] virtio-rng: Bump up quota value only when guest requests entropy, Michael S. Tsirkin, 2015/07/13