the IO-APIC automatically retry the transmission, so it should not be a big
problem, but you should read the SMP-FAQ.
-In this context it could be interesting to note the new irq directory in 2.4.
+In 2.6.2* /proc/interrupts was expanded again. This time the goal was for
+/proc/interrupts to display every IRQ vector in use by the system, not
+just those considered 'most important'. The new vectors are:
+
+ THR -- interrupt raised when a machine check threshold counter
+ (typically counting ECC corrected errors of memory or cache) exceeds
+ a configurable threshold. Only available on some systems.
+
+ TRM -- a thermal event interrupt occurs when a temperature threshold
+ has been exceeded for the CPU. This interrupt may also be generated
+ when the temperature drops back to normal.
+
+ SPU -- a spurious interrupt is some interrupt that was raised then lowered
+ by some IO device before it could be fully processed by the APIC. Hence
+ the APIC sees the interrupt but does not know what device it came from.
+ For this case the APIC will generate the interrupt with a IRQ vector
+ of 0xff. This might also be generated by chipset bugs.
+
+ RES, CAL, TLB -- rescheduling, call and TLB flush interrupts are
+ sent from one CPU to another per the needs of the OS. Typically,
+ their statistics are used by kernel developers and interested users to
+ determine the occurance of interrupt of the given type.
+
+The above IRQ vectors are displayed only when relevent. For example,
+the threshold vector does not exist on x86_64 platforms. Others are
+suppressed when the system is a uniprocessor. As of this writing, only
+i386 and x86_64 platforms support the new IRQ vector displays.
+
+Of some interest is the introduction of the /proc/irq directory to 2.4.
It could be used to set IRQ to CPU affinity, this means that you can "hook" an
IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the
irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask
since the system first booted. For a quick look, simply cat the file:
> cat /proc/stat
- cpu 2255 34 2290 22625563 6290 127 456
- cpu0 1132 34 1441 11311718 3675 127 438
- cpu1 1123 0 849 11313845 2614 0 18
+ cpu 2255 34 2290 22625563 6290 127 456 0
+ cpu0 1132 34 1441 11311718 3675 127 438 0
+ cpu1 1123 0 849 11313845 2614 0 18 0
intr 114930548 113199788 3 0 5 263 0 4 [... lots more numbers ...]
ctxt 1990473
btime 1062191376
- iowait: waiting for I/O to complete
- irq: servicing interrupts
- softirq: servicing softirqs
+- steal: involuntary wait
The "intr" line gives counts of interrupts serviced since boot time, for each
of the possible system interrupts. The first column is the total of all
The "procs_blocked" line gives the number of processes currently blocked,
waiting for I/O to complete.
+1.9 Ext4 file system parameters
+------------------------------
+Ext4 file system have one directory per partition under /proc/fs/ext4/
+# ls /proc/fs/ext4/hdc/
+group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req
+stats stream_req
+
+mb_groups:
+This file gives the details of mutiblock allocator buddy cache of free blocks
+
+mb_history:
+Multiblock allocation history.
+
+stats:
+This file indicate whether the multiblock allocator should start collecting
+statistics. The statistics are shown during unmount
+
+group_prealloc:
+The multiblock allocator normalize the block allocation request to
+group_prealloc filesystem blocks if we don't have strip value set.
+The stripe value can be specified at mount time or during mke2fs.
+
+max_to_scan:
+How long multiblock allocator can look for a best extent (in found extents)
+
+min_to_scan:
+How long multiblock allocator must look for a best extent
+
+order2_req:
+Multiblock allocator use 2^N search using buddies only for requests greater
+than or equal to order2_req. The request size is specfied in file system
+blocks. A value of 2 indicate only if the requests are greater than or equal
+to 4 blocks.
+
+stream_req:
+Files smaller than stream_req are served by the stream allocator, whose
+purpose is to pack requests as close each to other as possible to
+produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16
+filesystem block size will use group based preallocation.
------------------------------------------------------------------------------
Summary
resume it if we have a value of 3 or more percent; consider information about
the amount of free space valid for 30 seconds
-audit_argv_kb
--------------
-
-The file contains a single value denoting the limit on the argv array size
-for execve (in KiB). This limit is only applied when system call auditing for
-execve is enabled, otherwise the value is ignored.
-
ctrl-alt-del
------------
Maximum size of the routing cache. Old entries will be purged once the cache
reached has this size.
-max_delay, min_delay
---------------------
-
-Delays for flushing the routing cache.
-
redirect_load, redirect_number
------------------------------
projects / linux-2.6-omap-h63xx.git / blobdiff