From: Eric Dumazet <eric.dumazet@gmail.com>
To: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: regression with napi/softirq ?
Date: Thu, 18 Jul 2019 17:08:20 +0200 [thread overview]
Message-ID: <870de0d9-5c08-9431-a46a-33ee4d3a6617@gmail.com> (raw)
In-Reply-To: <CADVatmPQRf9A9z1LbHe5cd+bFLrPGG12YxPh2-yXAj_C9s8ZeA@mail.gmail.com>
On 7/18/19 2:55 PM, Sudip Mukherjee wrote:
> Thanks Eric. But there is no improvement in delay between
> softirq_raise and softirq_entry with this change.
> But moving to a later kernel (linus master branch? ) like Thomas has
> said in the other mail might be difficult atm. I can definitely
> move to v4.14.133 if that helps. Thomas ?
If you are tracking max latency then I guess you have to tweak SOFTIRQ_NOW_MASK
to include NET_RX_SOFTIRQ
The patch I gave earlier would only lower the probability of events, not completely get rid of them.
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 0427a86743a46b7e1891f7b6c1ff585a8a1695f5..302046dd8d7e6740e466c422954f22565fe19e69 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -81,7 +81,7 @@ static void wakeup_softirqd(void)
* right now. Let ksoftirqd handle this at its own rate, to get fairness,
* unless we're doing some of the synchronous softirqs.
*/
-#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ))
+#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ) | (1 << NET_RX_SOFTIRQ))
static bool ksoftirqd_running(unsigned long pending)
{
struct task_struct *tsk = __this_cpu_read(ksoftirqd);
next prev parent reply other threads:[~2019-07-18 15:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 20:19 regression with napi/softirq ? Sudip Mukherjee
2019-07-17 20:53 ` Thomas Gleixner
2019-07-17 21:40 ` Sudip Mukherjee
2019-07-17 21:52 ` Thomas Gleixner
2019-07-18 6:58 ` Eric Dumazet
2019-07-18 11:18 ` Sudip Mukherjee
2019-07-18 11:42 ` Eric Dumazet
2019-07-18 12:55 ` Sudip Mukherjee
2019-07-18 15:08 ` Eric Dumazet [this message]
2019-07-19 15:53 ` Sudip Mukherjee
2019-07-18 12:40 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=870de0d9-5c08-9431-a46a-33ee4d3a6617@gmail.com \
--to=eric.dumazet@gmail.com \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=sudipm.mukherjee@gmail.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).