No description
8635c016db
The fastboot command currently uses USBDEVFS_BULK to transfer data (including image data) to the target. On the kernel side it looks like this: 1. Allocate a contiguous memory region and copy the user data into the memory region (which may involve accessing storage). 2. Instruct the driver to start a DMA operation. 3. Wait for the DMA to finish. This is suboptimal because it misses out on a pipelining opportunity. We could be doing 3 for the current operation in parallel with 1 for the next operation, so that the next DMA is ready to go as soon as the current DMA finishes. The kernel supports asynchronous operations on usbdevfs file descriptors (USBDEVFS_SUBMITURB and USBDEVFS_REAPURB), so we can implement this like so: 1. Submit URB 0 2. Submit URB 1 3. Wait for URB 0 4. Submit URB 2 5. Wait for URB 1 and so on. That is what this CL implements. On my machine it increases transfer speed from 125 MB/s to 160 MB/s using a USB 3.0 connection to the target (Pixel 8). Bug: 324107907 Change-Id: I20db7ea14af85db48f6494091c8279ef7a21033d |
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| bootstat | ||
| cli-test | ||
| code_coverage | ||
| debuggerd | ||
| diagnose_usb | ||
| fastboot | ||
| fs_mgr | ||
| gatekeeperd | ||
| healthd | ||
| include | ||
| init | ||
| janitors | ||
| libappfuse | ||
| libasyncio | ||
| libcrypto_utils | ||
| libcutils | ||
| libgrallocusage | ||
| libkeyutils | ||
| libmodprobe | ||
| libnetutils | ||
| libpackagelistparser | ||
| libprocessgroup | ||
| libsparse | ||
| libstats | ||
| libsuspend | ||
| libsync | ||
| libsystem | ||
| libsysutils | ||
| libusbhost | ||
| libutils | ||
| libvendorsupport | ||
| libvndksupport | ||
| llkd | ||
| mini_keyctl | ||
| mkbootfs | ||
| property_service | ||
| reboot | ||
| rootdir | ||
| run-as | ||
| sdcard | ||
| shell_and_utilities | ||
| storaged | ||
| toolbox | ||
| trusty | ||
| usbd | ||
| watchdogd | ||
| .clang-format | ||
| .clang-format-2 | ||
| .clang-format-4 | ||
| .gitignore | ||
| CleanSpec.mk | ||
| METADATA | ||
| MODULE_LICENSE_APACHE2 | ||
| OWNERS | ||
| PREUPLOAD.cfg | ||
| rustfmt.toml | ||