I had not understood how MSIs work and I was unnecessarily routing them
through IOAPIC. This is not necessary and should not be done :D
Also MSIs were reserving interrupts that IOAPIC was capable of
generating. Now IOAPIC and MSIs use different set of interrupts so
IOAPIC can use more interrupts if needed.
Change Semaphore -> ThreadBlocker
This was not a semaphore, I just named it one because I didn't know
what semaphore was. I have meant to change this sooner, but it was in
no way urgent :D
Implement SMP events. Processors can now be sent SMP events through
IPIs. SMP events can be sent either to a single processor or broadcasted
to every processor.
PageTable::{map_page,map_range,unmap_page,unmap_range}() now send SMP
event to invalidate TLB caches for the changed pages.
Scheduler no longer uses a global run queue. Each processor has its own
scheduler that keeps track of the load on the processor. Once every
second schedulers do load balancing. Schedulers have no access to other
processors' schedulers, they just see approximate loads. If scheduler
decides that it has too much load, it will send a thread to another
processor through a SMP event.
Schedulers are currently run using the timer interrupt on BSB. This
should be not the case, and each processor should use its LAPIC timer
for interrupts. There is no reason to broadcast SMP event to all
processors when BSB gets timer interrupt.
Old scheduler only achieved 20% idle load on qemu. That was probably a
very inefficient implementation. This new scheduler seems to average
around 1% idle load. This is much closer to what I would expect. On my
own laptop idle load seems to be only around 0.5% on each processor.
ATADevice now stores its name instead of using static buffer. Old
static buffer was changing on every name query. I just hadn't noticed
since virtual machine disks were always sda.
SATA drives can now be used with banan-os. This allows much faster
disk access (writing 10 MiB from 30s to 1.5s). This can definitely
be optimized but the main slow down is probably the whole disk
structure in the os.
AHCI drive is now the default when running qemu.
SpinLock and RecursiveSpinLock will now allow locking after the initial
locker is invalid. This allows us to kill threads even if they are holding
internal locks
We now have DevFileSystem which is derived from RamFileSystem. All
devices are RamInodes. We don't have separate DeviceManager anymore.
To iterate over devices, you can loop througn every inode in devfs.
DiskCache now consists of PageCaches which are caches of contiguous
sectors. This allows the disk cache to be ordered and faster traversal.
We seem to have a problem somewhere during reading. The stack gets
corrupted.
Reading is now much slower at ~500 kB/s it was around 3 MB/s.
This is probably mostly due semaphore blocking taking atleast
until next reschedule (1 ms itervals). This will be a problem
as long as we are using only single processor.
I could try to use {READ/WRITE}_MULTIPLE commands, but since
most of the disk reads are 2 sectors (inode block size) this
will at most double the speed.
Most efficient speed up would of course be caching disk access
data and inodes overall.
The API is kinda weird since device reads/writes go from
ATADevice -> ATAController -> ATADevice
but this is for now atleast necessary since ATAController has(?)
to keep all devices from using the disks at the same time
We used to block on all process access. This meant that shell
reading the keyboard input would block all VFS access making disk
accesses practically impossible. We now block only when it is
necessary :)
Bananymous
Bananymous