> does using MSI or MSI-X save any power or have any other benefit? - Advanced on multiple CPU: MSI-X can handle interrupt asynchronously on different CPU cores. - Device Stability: "Storm interrupt" by malfunction devices or drivers affect by using shared interrupt. MSI/MSI-X does not use shared interrupt and therefore more stability on device. - Performance: better performance compare to legacy interrupt, specially for streaming devices. Thanks, Dong -----Original Message----- From: Sarah Sharp [mailto:sarah.a.sharp@xxxxxxxxxxxxxxx] Sent: Tuesday, May 04, 2010 11:49 AM To: David Vrabel Cc: Xu, Andiry; linux-usb@xxxxxxxxxxxxxxx; gregkh@xxxxxxx; Nguyen, Dong; Yang, Libin Subject: Re: [PATCH] xHCI: supporting MSI/MSI-X On Tue, May 04, 2010 at 03:24:51PM +0100, David Vrabel wrote: > Andiry Xu wrote: > > + for (i = 0; i < xhci->msix_count; i++) { > > + fn = (irq_handler_t)xhci_msi_irq; > > + ret = request_irq(xhci->msix_entries[i].vector, > > + fn, 0, "xhci_hcd", xhci_to_hcd(xhci)); > > + if (ret) > > + goto disable_msix; > > + } > > Are multiple vectors useful if they all use the same interrupt handler > that locks the same spinlock? This patch is also less useful because it doesn't add a new event ring per MSI-X interrupter. (Each USB device's events can be directed to a different event ring.) Making each interrupt handler use a different spinlock doesn't make sense until we give each interrupter a separate event ring to process. Andiry, does using MSI or MSI-X save any power or have any other benefit? Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
