[libvirt] [PATCH 3/5] blockjob: optimize JSON event handler lookup
Daniel Veillard
veillard at redhat.com
Thu Apr 12 01:15:59 UTC 2012
On Wed, Apr 11, 2012 at 05:40:36PM -0600, Eric Blake wrote:
> Probably in the noise, but this will let us scale more efficiently
> as we recognize ever more qemu events.
s/ever/even/
> * src/qemu/qemu_monitor_json.c (eventHandlers): Sort.
> (eventSearch): New helper function.
> (qemuMonitorJSONIOProcessEvent): Optimize event lookup.
> ---
> src/qemu/qemu_monitor_json.c | 54 ++++++++++++++++++++++++------------------
> 1 files changed, 31 insertions(+), 23 deletions(-)
>
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index d4d2c3e..f7d9ef2 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -66,36 +66,45 @@ static void qemuMonitorJSONHandleTrayChange(qemuMonitorPtr mon, virJSONValuePtr
> static void qemuMonitorJSONHandlePMWakeup(qemuMonitorPtr mon, virJSONValuePtr data);
> static void qemuMonitorJSONHandlePMSuspend(qemuMonitorPtr mon, virJSONValuePtr data);
>
> -static struct {
> +typedef struct {
> const char *type;
> void (*handler)(qemuMonitorPtr mon, virJSONValuePtr data);
> -} eventHandlers[] = {
> - { "SHUTDOWN", qemuMonitorJSONHandleShutdown, },
> - { "RESET", qemuMonitorJSONHandleReset, },
> - { "POWERDOWN", qemuMonitorJSONHandlePowerdown, },
> - { "STOP", qemuMonitorJSONHandleStop, },
> - { "RTC_CHANGE", qemuMonitorJSONHandleRTCChange, },
> - { "WATCHDOG", qemuMonitorJSONHandleWatchdog, },
> +} qemuEventHandler;
> +static qemuEventHandler eventHandlers[] = {
> { "BLOCK_IO_ERROR", qemuMonitorJSONHandleIOError, },
> - { "VNC_CONNECTED", qemuMonitorJSONHandleVNCConnect, },
> - { "VNC_INITIALIZED", qemuMonitorJSONHandleVNCInitialize, },
> - { "VNC_DISCONNECTED", qemuMonitorJSONHandleVNCDisconnect, },
> { "BLOCK_JOB_COMPLETED", qemuMonitorJSONHandleBlockJob, },
> + { "DEVICE_TRAY_MOVED", qemuMonitorJSONHandleTrayChange, },
> + { "POWERDOWN", qemuMonitorJSONHandlePowerdown, },
> + { "RESET", qemuMonitorJSONHandleReset, },
> + { "RTC_CHANGE", qemuMonitorJSONHandleRTCChange, },
> + { "SHUTDOWN", qemuMonitorJSONHandleShutdown, },
> { "SPICE_CONNECTED", qemuMonitorJSONHandleSPICEConnect, },
> - { "SPICE_INITIALIZED", qemuMonitorJSONHandleSPICEInitialize, },
> { "SPICE_DISCONNECTED", qemuMonitorJSONHandleSPICEDisconnect, },
> - { "DEVICE_TRAY_MOVED", qemuMonitorJSONHandleTrayChange, },
> - { "WAKEUP", qemuMonitorJSONHandlePMWakeup, },
> + { "SPICE_INITIALIZED", qemuMonitorJSONHandleSPICEInitialize, },
> + { "STOP", qemuMonitorJSONHandleStop, },
> { "SUSPEND", qemuMonitorJSONHandlePMSuspend, },
> + { "VNC_CONNECTED", qemuMonitorJSONHandleVNCConnect, },
> + { "VNC_DISCONNECTED", qemuMonitorJSONHandleVNCDisconnect, },
> + { "VNC_INITIALIZED", qemuMonitorJSONHandleVNCInitialize, },
> + { "WAKEUP", qemuMonitorJSONHandlePMWakeup, },
> + { "WATCHDOG", qemuMonitorJSONHandleWatchdog, },
> + /* We use bsearch, so keep this list sorted. */
> };
>
> +static int
> +qemuMonitorEventCompare(const void *key, const void *elt)
> +{
> + const char *type = key;
> + const qemuEventHandler *handler = elt;
> + return strcmp(type, handler->type);
> +}
>
> static int
> qemuMonitorJSONIOProcessEvent(qemuMonitorPtr mon,
> virJSONValuePtr obj)
> {
> const char *type;
> - int i;
> + qemuEventHandler *handler;
> VIR_DEBUG("mon=%p obj=%p", mon, obj);
>
> type = virJSONValueObjectGetString(obj, "event");
> @@ -105,14 +114,13 @@ qemuMonitorJSONIOProcessEvent(qemuMonitorPtr mon,
> return -1;
> }
>
> - for (i = 0 ; i < ARRAY_CARDINALITY(eventHandlers) ; i++) {
> - if (STREQ(eventHandlers[i].type, type)) {
> - virJSONValuePtr data = virJSONValueObjectGet(obj, "data");
> - VIR_DEBUG("handle %s handler=%p data=%p", type,
> - eventHandlers[i].handler, data);
> - (eventHandlers[i].handler)(mon, data);
> - break;
> - }
> + handler = bsearch(type, eventHandlers, ARRAY_CARDINALITY(eventHandlers),
> + sizeof(eventHandlers[0]), qemuMonitorEventCompare);
> + if (handler) {
> + virJSONValuePtr data = virJSONValueObjectGet(obj, "data");
> + VIR_DEBUG("handle %s handler=%p data=%p", type,
> + handler->handler, data);
> + (handler->handler)(mon, data);
> }
> return 0;
> }
Okay, this should speed up the lookups somehow. I also appreciate
separating the type and the array variable declaration,
ACK
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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