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  1. 24 6月, 2020 5 次提交
    • Y
      alinux: sched: Finer grain of sched latency · fa418988
      由 Yihao Wu 提交于 
      to #28739709

Many samples are between 10ms-50ms. To display more informative
distribution of latency, divide 10ms-50ms into 5 parts uniformly.

Example:

  $ cat /sys/fs/cgroup/cpuacct/a/cpuacct.wait_latency
	0-1ms: 	59726433
	1-4ms: 	167
	4-7ms: 	0
	7-10ms: 	0
	10-20ms: 	5
	20-30ms: 	0
	30-40ms: 	3
	40-50ms: 	0
	50-100ms: 	0
	100-500ms: 	0
	500-1000ms: 	0
	1000-5000ms: 	0
	5000-10000ms: 	0
	>=10000ms: 	0
	total(ms): 	45554
	nr: 	59726600
Signed-off-by: NYihao Wu <wuyihao@linux.alibaba.com>
Acked-by: NMichael Wang <yun.wang@linux.alibaba.com>
      fa418988
    • Y
      alinux: sched: Add "nr" to sched latency histogram · 2abfd07b
      由 Yihao Wu 提交于 
      to #28739709

Sometimes histogram is not precise enough because each sample is
roughly accounted into a histogram bar. And average latency is more
pratical for some users.

This patch adds a "nr" field in 4 latency histogram interfaces, so

	lat(avg) = total(ms) / nr

And compared to histogram, average latency is better to be used as a
SLI because of simplicity.

Example

    $ cat /sys/fs/cgroup/cpuacct/a/cpuacct.wait_latency
      0-1ms:  4139
      1-4ms:  317
      4-7ms:  568
      7-10ms:         0
      10-100ms:       42324
      100-500ms:      9131
      500-1000ms:     95
      1000-5000ms:    134
      5000-10000ms:   0
      >=10000ms:      0
      total(ms):      4256455
      nr:      182128
Signed-off-by: NYihao Wu <wuyihao@linux.alibaba.com>
Acked-by: NMichael Wang <yun.wang@linux.alibaba.com>
      2abfd07b
    • Y
      alinux: sched: Add cgroup's scheduling latency histograms · 6dbaddaa
      由 Yihao Wu 提交于 
      to #28739709

This patch adds cpuacct.cgroup_wait_latency interface. It exports the
histogram of the sched entity's schedule latency. Unlike wait_latency,
the sched entity is a cgroup rather than task.

This is useful when tasks are not directly clustered under one cgroup.
For examples:

cgroup1 --- cgroupA --- task1
        --- cgroupB --- task2
cgroup2 --- cgroupC --- task3
        --- cgroupD --- task4

This is a common cgroup hierarchy used by many applications. With
cgroup_wait_latency, we can just read from cgroup1 to know aggregated
wait latency information of task1 and task2.

The interface output format is identical to cpuacct.wait_latency.
Signed-off-by: NYihao Wu <wuyihao@linux.alibaba.com>
Acked-by: NMichael Wang <yun.wang@linux.alibaba.com>
      6dbaddaa
    • Y
      alinux: sched: Add cgroup-level blocked time histograms · a055ee2c
      由 Yihao Wu 提交于 
      to #28739709

This patch measures time that tasks in cpuacct cgroup blocks. There
are two types: blocked due to IO, and others like locks. And they
are exported in"cpuacct.ioblock_latency" and "cpuacct.block_latency"
respectively.

According to histogram, we know the detailed distribution of the
duration. And according to total(ms), we know the percentage of time
tasks spent off rq, waiting for resources:

(△ioblock_latency.total(ms) + △block_latency.total(ms)) / △wall_time

The interface output format is identical to cpuacct.wait_latency.
Signed-off-by: NYihao Wu <wuyihao@linux.alibaba.com>
Acked-by: NXunlei Pang <xlpang@linux.alibaba.com>
Reviewed-by: NShanpei Chen <shanpeic@linux.alibaba.com>
Acked-by: NMichael Wang <yun.wang@linux.alibaba.com>
      a055ee2c
    • Y
      alinux: sched: Introduce cfs scheduling latency histograms · 76d98609
      由 Yihao Wu 提交于 
      to #28739709

Export wait_latency in "cpuacct.wait_latency", which indicates the
time that tasks in a cpuacct cgroup wait on a cfs_rq to be scheduled.

This is like "perf sched", but it gives smaller overhead. So it can
be used as monitor constantly.

wait_latency is useful to debug application's high RT problem. It can
tell if it's caused by scheduling or not. If it is, loadavg can tell
if it's caused by bad scheduling bahaviour or system overloads.

System admins can also use wait_latency to define SLA. To ensure SLA
is guaranteed, there are various ways to decrease wait_latency.

This feature is disabled by default for performance concerns. It can
be switched on dynamically by "echo 0 > /proc/cpusli/sched_lat_enable"

Example:

  $ cat /sys/fs/cgroup/cpuacct/a/cpuacct.wait_latency
    0-1ms:  4139
    1-4ms:  317
    4-7ms:  568
    7-10ms:         0
    10-100ms:       42324
    100-500ms:      9131
    500-1000ms:     95
    1000-5000ms:    134
    5000-10000ms:   0
    >=10000ms:      0
    total(ms):      4256455
Signed-off-by: NYihao Wu <wuyihao@linux.alibaba.com>
Acked-by: NXunlei Pang <xlpang@linux.alibaba.com>
Reviewed-by: NShanpei Chen <shanpeic@linux.alibaba.com>
Acked-by: NMichael Wang <yun.wang@linux.alibaba.com>
      76d98609
  3. 23 6月, 2020 13 次提交
  5. 22 6月, 2020 3 次提交
  7. 19 6月, 2020 1 次提交
    • X
      configs: arm64: use 48-bit virtual address · f44f084b
      由 Xu Yu 提交于 
      fix #28506983

Some ARM machines may have large memory capacity (e.g., more than 256G),
or large hole(s) in memory layout among nodes.

Kernel with CONFIG_ARM64_VA_BITS as 39 has the linear region size as
256G, and the memory that we will not be able to cover with the linear
mapping shall be removed. This may cause part of the physical memory to
become unavailable, system deadlock on memory, or even boot failure, on
such ARM machines.

This changes CONFIG_ARM64_VA_BITS to 48 which supports 128T linear
mapping, in order to adapt to most scenarios.
Signed-off-by: NXu Yu <xuyu@linux.alibaba.com>
Reviewed-by: NShile Zhang <shile.zhang@linux.alibaba.com>
Reviewed-by: NCaspar Zhang <caspar@linux.alibaba.com>
      f44f084b
  9. 16 6月, 2020 18 次提交