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How usecs_to_jiffies transforms usecs to jiffies if jiffies are in resolution of msecs?

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http://stackoverflow.com – from here: The value of HZ varies across kernel versions and hardware platforms. On i386 the situation is as follows: on kernels up to and including 2.4.x, HZ was 100, giving a jiffy value of 0.01 seconds; starting with 2.6.0, HZ was raised to 1000, giving a jiffy of 0.001 seconds. Since kernel 2.6.13, the HZ value is a kernel configuration parameter and can be 100, 250 (the default) or 1000, yielding a jiffies value of, respectively, 0.01, 0.004, or 0.001 seconds. Since kernel 2.6.20, a further frequency is available: 300, a number (HowTos)

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Submitted by dadebian on 02/04/2013

Stories similar to How usecs_to_jiffies transforms usecs to jiffies if jiffies are in resolution of msecs?

I know that jiffies length is selected at kernel compile time and it is defaulted to 250 (4ms). Source: man 7 time - The Software Clock, HZ, and Jiffies

I wonder what happens inside a jiffy. What are the conditions to increase the value of utime or stime in /proc/pid/stat?

I know that jiffies length is selected at kernel compile time and it is defaulted to 250 (4ms). Source: man 7 time - The Software Clock, HZ, and Jiffies

I wonder what happens inside a jiffy. What are the conditions to increase the value of utime or stime in /proc/pid/stat?

Reading from /proc/PID/stat a lot of information can be processed. I would like to see how many percentages has been used of CPU power by this process. There are a lot of variable around here (utime, stime, cutime, cstime, gtime, cgtime) but they are in jiffies. The problem with this that jiffy depends on speed of the current CPU.

To schedule an action to happen later in a linux kernel driver I have 2 options:

add_timer queue_delayed_work

One difference I know about: for timers you need to specify expires which is the jiffies value when the timer will expire, for delayed work you need to specify the delay of jiffies.

I've been reading other questions about timers and work_queue's, and it mentions timers run outside pro

If I have

A kernel with CONFIG_HIGH_RES_TIMERS=y, A coarse CONFIG_HZ (say, 100) and a file descriptor from timerfd_create with a sub-jiffy expiration

Should a call to select() on this timer return before the next jiffy, as say, clock_nanosleep would?

I couldnt post in the kernel thread because I don't have enough posts yet..

I installed clean Rom a month or so ago and have been updating to the new versions ever Since, everything had been running perfectly on the stock kernel. I got the itch to try a new kernel and decided to try out the elemental kernel (later tried the beast mode as well).

Ok, Chackra Linux rocks... this is Claire Final 2012.12, original kernel and a few tweaks.Listen to that...Less than 49 seconds to reach a functional KDE desktop, in a monoprocessor, 1.9 Ghz.Image above shows Linux Kernel time to boot, ~5 seconds, plus Systemd units load times, all = ~ 4 seconds.Not bad :-). Note the top of graph showing the total time spent by it.

so i am building a series of custom kernels...

for one of them i am using a kernel that is older than my currently installed ones.

i am using rpm to install this kernel and it will not install, period.

does anybody know a work around, i don't get why i can't install this....what does it matter

Hi,after different times of usage, I got a kernel panic with every kernel I tried since 3.4.9, but for that one I atleast got logs and saw some output on the screen iirc. The kernels I tried in the mean time include 3.5.3-1, 3.5.4-1, 3.6.2-1 and 3.6.5-1 and some -ck versions from the aur.