Re: [dpdk-dev] [PATCH v5 4/4] power: send confirmation cmd to vm guest

["Hunt, David" <david.hunt@intel.com>]

On 05/04/2019 14:24, Hajkowski wrote:
> From: Marcin Hajkowski <marcinx.hajkowski@intel.com>
>
> Use new guest channel API to send confirmation
> message for received power command.
>
> Signed-off-by: Marcin Hajkowski <marcinx.hajkowski@intel.com>
> ---
>   examples/vm_power_manager/channel_monitor.c | 68 +++++++++++++++++++--
>   1 file changed, 62 insertions(+), 6 deletions(-)
>
> diff --git a/examples/vm_power_manager/channel_monitor.c b/examples/vm_power_manager/channel_monitor.c
> index 7892d75de..ed580b36a 100644
> --- a/examples/vm_power_manager/channel_monitor.c
> +++ b/examples/vm_power_manager/channel_monitor.c
> @@ -627,6 +627,41 @@ apply_policy(struct policy *pol)
>   		apply_workload_profile(pol);
>   }
>   
> +static int
> +write_binary_packet(struct channel_packet *pkt, struct channel_info *chan_info)
> +{
> +	int ret, buffer_len = sizeof(*pkt);
> +	void *buffer = pkt;
> +
> +	if (chan_info->fd < 0) {
> +		RTE_LOG(ERR, CHANNEL_MONITOR, "Channel is not connected\n");
> +		return -1;
> +	}
> +
> +	while (buffer_len > 0) {
> +		ret = write(chan_info->fd, buffer, buffer_len);
> +		if (ret == -1) {
> +			if (errno == EINTR)
> +				continue;
> +			RTE_LOG(ERR, CHANNEL_MONITOR, "Write function failed due to %s.\n",
> +					strerror(errno));
> +			return -1;
> +		}
> +		buffer = (char *)buffer + ret;
> +		buffer_len -= ret;
> +	}
> +	return 0;
> +}
> +
> +static int
> +send_ack_for_received_cmd(struct channel_packet *pkt,
> +		struct channel_info *chan_info,
> +		uint32_t command)
> +{
> +	pkt->command = command;
> +	return write_binary_packet(pkt, chan_info);
> +}
> +
>   static int
>   process_request(struct channel_packet *pkt, struct channel_info *chan_info)
>   {
> @@ -650,33 +685,54 @@ process_request(struct channel_packet *pkt, struct channel_info *chan_info)
>   		RTE_LOG(DEBUG, CHANNEL_MONITOR, "Processing requested cmd for cpu:%d\n",
>   			core_num);
>   
> +		bool valid_unit = true;
> +		int scale_res;
> +
>   		switch (pkt->unit) {
>   		case(CPU_POWER_SCALE_MIN):
> -			power_manager_scale_core_min(core_num);
> +			scale_res = power_manager_scale_core_min(core_num);
>   			break;
>   		case(CPU_POWER_SCALE_MAX):
> -			power_manager_scale_core_max(core_num);
> +			scale_res = power_manager_scale_core_max(core_num);
>   			break;
>   		case(CPU_POWER_SCALE_DOWN):
> -			power_manager_scale_core_down(core_num);
> +			scale_res = power_manager_scale_core_down(core_num);
>   			break;
>   		case(CPU_POWER_SCALE_UP):
> -			power_manager_scale_core_up(core_num);
> +			scale_res = power_manager_scale_core_up(core_num);
>   			break;
>   		case(CPU_POWER_ENABLE_TURBO):
> -			power_manager_enable_turbo_core(core_num);
> +			scale_res = power_manager_enable_turbo_core(core_num);
>   			break;
>   		case(CPU_POWER_DISABLE_TURBO):
> -			power_manager_disable_turbo_core(core_num);
> +			scale_res = power_manager_disable_turbo_core(core_num);
>   			break;
>   		default:
> +			valid_unit = false;
>   			break;
>   		}
> +
> +		if (valid_unit) {
> +			ret = send_ack_for_received_cmd(pkt,
> +					chan_info,
> +					scale_res > 0 ?
> +						CPU_POWER_CMD_ACK :
> +						CPU_POWER_CMD_NACK);
> +			if (ret < 0)
> +				RTE_LOG(DEBUG, CHANNEL_MONITOR, "Error during sending ack command.\n");
> +		} else
> +			RTE_LOG(DEBUG, CHANNEL_MONITOR, "Unexpected unit type.\n");
> +
>   	}
>   
>   	if (pkt->command == PKT_POLICY) {
>   		RTE_LOG(INFO, CHANNEL_MONITOR, "Processing policy request %s\n",
>   				pkt->vm_name);
> +		int ret = send_ack_for_received_cmd(pkt,
> +				chan_info,
> +				CPU_POWER_CMD_ACK);
> +		if (ret < 0)
> +			RTE_LOG(DEBUG, CHANNEL_MONITOR, "Error during sending ack command.\n");
>   		update_policy(pkt);
>   		policy_is_set = 1;
>   	}

Using the guest_cli sample app in a VM, sending commands to the 
vm_power_manager app on the host, we now have Acks and Nacks coming from 
the host to the VM to conform the execution of the guest requests.

vmpower(guest)> set_cpu_freq 3 down
ACK received for message sent to host.
vmpower(guest)> set_cpu_freq 3 up
ACK received for message sent to host.
vmpower(guest)> set_cpu_freq 3 up
NACK received for message sent to host.

(NACK because we're already at the maxumum frequency)

And in the host vm_power_manager command line, we can see when a guest 
request cannot be processed:
POWER: Turbo is off, frequency can't be scaled up more 31

Patchset looks good functionally.

Tested-by: David Hunt <david.hunt@intel.com>